diff --git a/.licenses/npm/undici.dep.yml b/.licenses/npm/undici.dep.yml
index c46a5c7..3368117 100644
--- a/.licenses/npm/undici.dep.yml
+++ b/.licenses/npm/undici.dep.yml
@@ -1,6 +1,6 @@
 ---
 name: undici
-version: 6.27.0
+version: 6.29.0
 type: npm
 summary: An HTTP/1.1 client, written from scratch for Node.js
 homepage: https://undici.nodejs.org
diff --git a/dist/index.js b/dist/index.js
index 06ae5d2..5cbece6 100644
--- a/dist/index.js
+++ b/dist/index.js
@@ -6846,11 +6846,77 @@ class Request {
     }
   }
 
-  onUpgrade (statusCode, headers, socket) {
+  /**
+   * @param {number|null} statusCode
+   * @param {Buffer[]|null} headers
+   * @param {import('node:stream').Duplex} socket
+   * @param {string} [statusText]
+   */
+  onUpgrade (statusCode, headers, socket, statusText = '') {
+    this.onFinally()
+
     assert(!this.aborted)
     assert(!this.completed)
 
-    return this[kHandler].onUpgrade(statusCode, headers, socket)
+    if (statusCode !== null) {
+      this.#publishUpgradeHeaders(statusCode, headers, statusText)
+    }
+
+    const result = this[kHandler].onUpgrade(statusCode, headers, socket)
+
+    if (!this.aborted) {
+      this.completed = true
+      if (statusCode !== null) {
+        this.#publishUpgradeTrailers()
+      }
+    }
+
+    return result
+  }
+
+  /**
+   * @param {number} statusCode
+   * @param {import('node:http2').IncomingHttpHeaders} headers
+   * @param {(headers: import('node:http2').IncomingHttpHeaders) => Buffer[]} parseHeaders
+   * @param {string} [statusText]
+   */
+  onUpgradeResponse (statusCode, headers, parseHeaders, statusText = '') {
+    assert(!this.aborted)
+    assert(this.completed)
+
+    if (channels.headers.hasSubscribers) {
+      this.#publishUpgradeHeaders(statusCode, parseHeaders(headers), statusText)
+    }
+    this.#publishUpgradeTrailers()
+  }
+
+  /**
+   * @param {Error} error
+   */
+  onUpgradeError (error) {
+    assert(!this.aborted)
+    assert(this.completed)
+
+    if (channels.error.hasSubscribers) {
+      channels.error.publish({ request: this, error })
+    }
+  }
+
+  /**
+   * @param {number} statusCode
+   * @param {Buffer[]} headers
+   * @param {string} statusText
+   */
+  #publishUpgradeHeaders (statusCode, headers, statusText) {
+    if (channels.headers.hasSubscribers) {
+      channels.headers.publish({ request: this, response: { statusCode, headers, statusText } })
+    }
+  }
+
+  #publishUpgradeTrailers () {
+    if (channels.trailers.hasSubscribers) {
+      channels.trailers.publish({ request: this, trailers: [] })
+    }
   }
 
   onComplete (trailers) {
@@ -6933,7 +6999,13 @@ function processHeader (request, key, val) {
       } else if (typeof val[i] === 'object') {
         throw new InvalidArgumentError(`invalid ${key} header`)
       } else {
-        arr.push(`${val[i]}`)
+        // Coerce primitives (and reject unsafe coercions such as functions
+        // with a crafted toString/Symbol.toPrimitive).
+        const str = `${val[i]}`
+        if (!isValidHeaderValue(str)) {
+          throw new InvalidArgumentError(`invalid ${key} header`)
+        }
+        arr.push(str)
       }
     }
     val = arr
@@ -6944,7 +7016,12 @@ function processHeader (request, key, val) {
   } else if (val === null) {
     val = ''
   } else {
+    // Coerce primitives (and reject unsafe coercions such as functions
+    // with a crafted toString/Symbol.toPrimitive).
     val = `${val}`
+    if (!isValidHeaderValue(val)) {
+      throw new InvalidArgumentError(`invalid ${key} header`)
+    }
   }
 
   if (headerName === 'host') {
@@ -8316,6 +8393,7 @@ const {
   RequestContentLengthMismatchError,
   ResponseContentLengthMismatchError,
   RequestAbortedError,
+  InvalidArgumentError,
   HeadersTimeoutError,
   HeadersOverflowError,
   SocketError,
@@ -8737,7 +8815,7 @@ class Parser {
   }
 
   onUpgrade (head) {
-    const { upgrade, client, socket, headers, statusCode } = this
+    const { upgrade, client, socket, headers, statusCode, statusText } = this
 
     assert(upgrade)
     assert(client[kSocket] === socket)
@@ -8772,9 +8850,10 @@ class Parser {
     client.emit('disconnect', client[kUrl], [client], new InformationalError('upgrade'))
 
     try {
-      request.onUpgrade(statusCode, headers, socket)
-    } catch (err) {
-      util.destroy(socket, err)
+      request.onUpgrade(statusCode, headers, socket, statusText)
+    } catch (error) {
+      util.errorRequest(client, request, error)
+      util.destroy(socket, error)
     }
 
     client[kResume]()
@@ -9181,7 +9260,7 @@ async function connectH1 (client, socket) {
 
 function clearIdleSocketValidation (socket) {
   if (socket[kIdleSocketValidationTimeout]) {
-    clearTimeout(socket[kIdleSocketValidationTimeout])
+    clearImmediate(socket[kIdleSocketValidationTimeout])
     socket[kIdleSocketValidationTimeout] = null
   }
 
@@ -9190,15 +9269,23 @@ function clearIdleSocketValidation (socket) {
 
 function scheduleIdleSocketValidation (client, socket) {
   socket[kIdleSocketValidation] = 1
-  socket[kIdleSocketValidationTimeout] = setTimeout(() => {
+  // Yield to the check phase (after poll) so unsolicited bytes / FIN / RST
+  // already pending on this idle keep-alive socket are processed before the
+  // next request is written (GHSA-35p6-xmwp-9g52).
+  //
+  // setTimeout(0) pays Node's ~1ms timer floor on every sequential reuse
+  // (#5493). setImmediate avoids that, but an *unref'd* Immediate lets poll
+  // block for ~500ms when the event loop is otherwise idle (#5600 / #5606).
+  // A ref'd Immediate both keeps the pending request alive and makes poll
+  // return immediately — the hybrid those issues asked for.
+  socket[kIdleSocketValidationTimeout] = setImmediate(() => {
     socket[kIdleSocketValidationTimeout] = null
     socket[kIdleSocketValidation] = 2
 
     if (client[kSocket] === socket && !socket.destroyed) {
       client[kResume]()
     }
-  }, 0)
-  socket[kIdleSocketValidationTimeout].unref?.()
+  })
 }
 
 /**
@@ -9299,8 +9386,16 @@ function writeH1 (client, request) {
     }
     body = bodyStream.stream
     contentLength = bodyStream.length
-  } else if (util.isBlobLike(body) && request.contentType == null && body.type) {
-    headers.push('content-type', body.type)
+  } else if (util.isBlobLike(body) && request.contentType == null) {
+    const contentType = body.type
+    if (contentType) {
+      const contentTypeValue = `${contentType}`
+      if (!util.isValidHeaderValue(contentTypeValue)) {
+        util.errorRequest(client, request, new InvalidArgumentError('invalid content-type header'))
+        return false
+      }
+      headers.push('content-type', contentTypeValue)
+    }
   }
 
   if (body && typeof body.read === 'function') {
@@ -9339,12 +9434,22 @@ function writeH1 (client, request) {
   const socket = client[kSocket]
   clearIdleSocketValidation(socket)
 
-  const abort = (err) => {
-    if (request.aborted || request.completed) {
+  /**
+   * @param {Error} [error]
+   */
+  const abort = (error) => {
+    if (request.aborted) {
       return
     }
 
-    util.errorRequest(client, request, err || new RequestAbortedError())
+    if (request.completed) {
+      if (request.upgrade || request.method === 'CONNECT') {
+        util.destroy(socket, new InformationalError('aborted'))
+      }
+      return
+    }
+
+    util.errorRequest(client, request, error || new RequestAbortedError())
 
     util.destroy(body)
     util.destroy(socket, new InformationalError('aborted'))
@@ -9801,6 +9906,7 @@ module.exports = connectH1
 
 
 const assert = __nccwpck_require__(4589)
+const { errorMonitor } = __nccwpck_require__(8474)
 const { pipeline } = __nccwpck_require__(7075)
 const util = __nccwpck_require__(3440)
 const {
@@ -9877,6 +9983,15 @@ function parseH2Headers (headers) {
   return result
 }
 
+/**
+ * @param {import('node:http2').IncomingHttpHeaders} headers
+ * @returns {Buffer[]}
+ */
+function parseH2ResponseHeaders (headers) {
+  const { [HTTP2_HEADER_STATUS]: _statusCode, ...realHeaders } = headers
+  return parseH2Headers(realHeaders)
+}
+
 async function connectH2 (client, socket) {
   client[kSocket] = socket
 
@@ -10097,22 +10212,32 @@ function writeH2 (client, request) {
   headers[HTTP2_HEADER_AUTHORITY] = host || `${hostname}${port ? `:${port}` : ''}`
   headers[HTTP2_HEADER_METHOD] = method
 
-  const abort = (err) => {
-    if (request.aborted || request.completed) {
+  /**
+   * @param {Error} [error]
+   */
+  const abort = (error) => {
+    if (request.aborted) {
       return
     }
 
-    err = err || new RequestAbortedError()
+    if (request.completed) {
+      if (method === 'CONNECT' && stream != null) {
+        util.destroy(stream, error || new RequestAbortedError())
+      }
+      return
+    }
 
-    util.errorRequest(client, request, err)
+    error = error || new RequestAbortedError()
+
+    util.errorRequest(client, request, error)
 
     if (stream != null) {
-      util.destroy(stream, err)
+      util.destroy(stream, error)
     }
 
     // We do not destroy the socket as we can continue using the session
     // the stream get's destroyed and the session remains to create new streams
-    util.destroy(body, err)
+    util.destroy(body, error)
     client[kQueue][client[kRunningIdx]++] = null
     client[kResume]()
   }
@@ -10131,25 +10256,57 @@ function writeH2 (client, request) {
 
   if (method === 'CONNECT') {
     session.ref()
-    // We are already connected, streams are pending, first request
-    // will create a new stream. We trigger a request to create the stream and wait until
-    // `ready` event is triggered
     // We disabled endStream to allow the user to write to the stream
     stream = session.request(headers, { endStream: false, signal })
+    let upgradeResponseFinished = false
 
-    if (stream.id && !stream.pending) {
-      request.onUpgrade(null, null, stream)
-      ++session[kOpenStreams]
-      client[kQueue][client[kRunningIdx]++] = null
-    } else {
-      stream.once('ready', () => {
-        request.onUpgrade(null, null, stream)
-        ++session[kOpenStreams]
-        client[kQueue][client[kRunningIdx]++] = null
-      })
+    /**
+     * @param {import('node:http2').IncomingHttpHeaders} headers
+     */
+    const onResponse = (headers) => {
+      upgradeResponseFinished = true
+      stream.off(errorMonitor, onUpgradeError)
+      request.onUpgradeResponse(Number(headers[HTTP2_HEADER_STATUS]), headers, parseH2ResponseHeaders)
     }
 
+    /**
+     * @param {Error} error
+     */
+    const onUpgradeError = (error) => {
+      upgradeResponseFinished = true
+      stream.off('response', onResponse)
+      request.onUpgradeError(error)
+    }
+
+    const onReady = () => {
+      try {
+        request.onUpgrade(null, null, stream)
+      } catch (error) {
+        stream.off('response', onResponse)
+        abort(error)
+        return
+      }
+
+      if (request.aborted) {
+        return
+      }
+
+      stream.off('error', abort)
+      stream.once(errorMonitor, onUpgradeError)
+      client[kQueue][client[kRunningIdx]++] = null
+    }
+
+    stream.once('response', onResponse)
+    stream.once('error', abort)
+    ++session[kOpenStreams]
+    onReady()
+
     stream.once('close', () => {
+      if (!upgradeResponseFinished && request.completed) {
+        stream.off('response', onResponse)
+        stream.off(errorMonitor, onUpgradeError)
+        request.onUpgradeError(new InformationalError(`HTTP/2: "stream error" received - code ${stream.rstCode}`))
+      }
       session[kOpenStreams] -= 1
       if (session[kOpenStreams] === 0) session.unref()
     })
@@ -12773,6 +12930,28 @@ function calculateRetryAfterHeader (retryAfter) {
   return new Date(retryAfter).getTime() - current
 }
 
+function validatePartialResponseContentLength (headers, range, statusCode, retryCount) {
+  const contentLength = headers['content-length']
+  if (contentLength == null) {
+    return null
+  }
+
+  if (!Number.isFinite(range.start) || !Number.isFinite(range.end)) {
+    return null
+  }
+
+  const length = Number(contentLength)
+  const expectedLength = range.end - range.start + 1
+  if (!Number.isFinite(length) || length !== expectedLength) {
+    return new RequestRetryError('Content-Length mismatch', statusCode, {
+      headers,
+      data: { count: retryCount }
+    })
+  }
+
+  return null
+}
+
 class RetryHandler {
   constructor (opts, handlers) {
     const { retryOptions, ...dispatchOpts } = opts
@@ -12826,6 +13005,7 @@ class RetryHandler {
     this.end = null
     this.etag = null
     this.resume = null
+    this.headersSent = false
 
     // Handle possible onConnect duplication
     this.handler.onConnect(reason => {
@@ -12838,6 +13018,20 @@ class RetryHandler {
     })
   }
 
+  checkpointResponseEnd (headers, resume) {
+    if (this.end == null && this.opts.method !== 'HEAD') {
+      const contentLength = headers['content-length']
+      this.end = contentLength != null ? Number(contentLength) - 1 : null
+
+      assert(
+        this.end == null || Number.isFinite(this.end),
+        'invalid content-length'
+      )
+    }
+
+    this.resume = this.end != null ? resume : null
+  }
+
   onRequestSent () {
     if (this.handler.onRequestSent) {
       this.handler.onRequestSent()
@@ -12926,7 +13120,12 @@ class RetryHandler {
     this.retryCount += 1
 
     if (statusCode >= 300) {
-      if (this.retryOpts.statusCodes.includes(statusCode) === false) {
+      // Only expose a response if no earlier attempt has reached the caller.
+      // Otherwise abort this attempt so the error settles the existing body
+      // instead of replacing it with a new response.
+      if (!this.headersSent && this.retryOpts.statusCodes.includes(statusCode) === false) {
+        this.headersSent = true
+        this.checkpointResponseEnd(headers, resume)
         return this.handler.onHeaders(
           statusCode,
           rawHeaders,
@@ -12987,10 +13186,23 @@ class RetryHandler {
         return false
       }
 
+      const contentLengthError = validatePartialResponseContentLength(headers, contentRange, statusCode, this.retryCount)
+      if (contentLengthError != null) {
+        this.abort(contentLengthError)
+        return false
+      }
+
       const { start, size, end = size - 1 } = contentRange
 
-      assert(this.start === start, 'content-range mismatch')
-      assert(this.end == null || this.end === end, 'content-range mismatch')
+      if (this.start !== start || (this.end != null && this.end !== end)) {
+        this.abort(
+          new RequestRetryError('Content-Range mismatch', statusCode, {
+            headers,
+            data: { count: this.retryCount }
+          })
+        )
+        return false
+      }
 
       this.resume = resume
       return true
@@ -13002,6 +13214,7 @@ class RetryHandler {
         const range = parseRangeHeader(headers['content-range'])
 
         if (range == null) {
+          this.headersSent = true
           return this.handler.onHeaders(
             statusCode,
             rawHeaders,
@@ -13010,6 +13223,12 @@ class RetryHandler {
           )
         }
 
+        const contentLengthError = validatePartialResponseContentLength(headers, range, statusCode, this.retryCount)
+        if (contentLengthError != null) {
+          this.abort(contentLengthError)
+          return false
+        }
+
         const { start, size, end = size - 1 } = range
         assert(
           start != null && Number.isFinite(start),
@@ -13034,6 +13253,7 @@ class RetryHandler {
       )
 
       this.resume = resume
+      this.headersSent = true
       this.etag = headers.etag != null ? headers.etag : null
 
       // Weak etags are not useful for comparison nor cache
@@ -13073,7 +13293,7 @@ class RetryHandler {
   }
 
   onError (err) {
-    if (this.aborted || isDisturbed(this.opts.body)) {
+    if (this.aborted || isDisturbed(this.opts.body) || (this.headersSent && this.resume == null)) {
       return this.handler.onError(err)
     }
 
@@ -17254,7 +17474,7 @@ function validateCookiePath (path) {
 
     if (
       code < 0x20 || // exclude CTLs (0-31)
-      code === 0x7F || // DEL
+      code > 0x7E || // exclude DEL and non-ascii
       code === 0x3B // ;
     ) {
       throw new Error('Invalid cookie path')
@@ -17263,16 +17483,80 @@ function validateCookiePath (path) {
 }
 
 /**
- * I have no idea why these values aren't allowed to be honest,
- * but Deno tests these. - Khafra
+ * <let-dig> ::= <letter> | <digit>
+ *
+ * <letter> ::= any one of the 52 alphabetic characters A through Z in
+ * upper case and a through z in lower case
+ *
+ * <digit> ::= any one of the ten digits 0 through 9r
+ *
+ * @see https://www.rfc-editor.org/rfc/rfc1034#section-3.5
+ * @param {number} code
+ */
+function isLetterOrDigit (code) {
+  return (
+    (code >= 0x30 && code <= 0x39) || // 0-9
+    (code >= 0x41 && code <= 0x5A) || // A-Z
+    (code >= 0x61 && code <= 0x7A) // a-z
+  )
+}
+
+/**
+ * Validates a cookie domain against the "preferred name syntax".
+ *
+ * <domain>      ::= <subdomain> | " "
+ * <subdomain>   ::= <label> | <subdomain> "." <label>
+ * <label>       ::= <let-dig> [ [ <ldh-str> ] <let-dig> ]
+ * <ldh-str>     ::= <let-dig-hyp> | <let-dig-hyp> <ldh-str>
+ * <let-dig-hyp> ::= <let-dig> | "-"
+ *
+ * @see https://www.rfc-editor.org/rfc/rfc1034#section-3.5
+ * @see https://www.rfc-editor.org/rfc/rfc1123#section-2.1
+ * @see https://www.rfc-editor.org/rfc/rfc1035#section-2.3.4
  * @param {string} domain
  */
 function validateCookieDomain (domain) {
-  if (
-    domain.startsWith('-') ||
-    domain.endsWith('.') ||
-    domain.endsWith('-')
-  ) {
+  // <domain> ::= <subdomain> | " "
+  if (domain === ' ') {
+    return
+  }
+
+  if (domain.length > 255) {
+    throw new Error('Invalid cookie domain')
+  }
+
+  let labelLength = 0
+
+  for (let i = 0; i < domain.length; ++i) {
+    const code = domain.charCodeAt(i)
+
+    if (code === 0x2E) {
+      if (labelLength === 0) {
+        throw new Error('Invalid cookie domain')
+      }
+
+      if (domain.charCodeAt(i - 1) === 0x2D) { // "-"
+        throw new Error('Invalid cookie domain')
+      }
+
+      labelLength = 0
+      continue
+    }
+
+    if (labelLength === 0 && !isLetterOrDigit(code)) {
+      throw new Error('Invalid cookie domain')
+    }
+
+    if (!isLetterOrDigit(code) && code !== 0x2D) { // "-"
+      throw new Error('Invalid cookie domain')
+    }
+
+    if (++labelLength > 63) {
+      throw new Error('Invalid cookie domain')
+    }
+  }
+
+  if (labelLength === 0 || domain.charCodeAt(domain.length - 1) === 0x2D) { // "-"
     throw new Error('Invalid cookie domain')
   }
 }
@@ -17415,7 +17699,13 @@ function stringify (cookie) {
 
     const [key, ...value] = part.split('=')
 
-    out.push(`${key.trim()}=${value.join('=')}`)
+    const trimmedKey = key.trim()
+    const joinedValue = value.join('=')
+
+    validateCookieName(trimmedKey)
+    validateCookieValue(joinedValue)
+
+    out.push(`${trimmedKey}=${joinedValue}`)
   }
 
   return out.join('; ')
@@ -17461,6 +17751,49 @@ const COLON = 0x3A
  */
 const SPACE = 0x20
 
+const DATA = Buffer.from('data')
+const EVENT = Buffer.from('event')
+const ID = Buffer.from('id')
+const RETRY = Buffer.from('retry')
+
+function isASCIINumberBytes (buffer, start) {
+  if (start >= buffer.length) {
+    return false
+  }
+
+  for (let i = start; i < buffer.length; i++) {
+    if (buffer[i] < 0x30 || buffer[i] > 0x39) {
+      return false
+    }
+  }
+
+  return true
+}
+
+function isValidLastEventIdBytes (buffer, start) {
+  for (let i = start; i < buffer.length; i++) {
+    if (buffer[i] === 0x00) {
+      return false
+    }
+  }
+
+  return true
+}
+
+function isFieldName (line, length, field) {
+  if (length !== field.length) {
+    return false
+  }
+
+  for (let i = 0; i < length; i++) {
+    if (line[i] !== field[i]) {
+      return false
+    }
+  }
+
+  return true
+}
+
 /**
  * @typedef {object} EventSourceStreamEvent
  * @type {object}
@@ -17501,11 +17834,14 @@ class EventSourceStream extends Transform {
   eventEndCheck = false
 
   /**
-   * @type {Buffer}
+   * @type {Buffer[]}
    */
-  buffer = null
+  chunks = []
 
+  chunkIndex = 0
   pos = 0
+  lineChunkIndex = 0
+  linePos = 0
 
   event = {
     data: undefined,
@@ -17544,92 +17880,20 @@ class EventSourceStream extends Transform {
       return
     }
 
-    // Cache the chunk in the buffer, as the data might not be complete while
-    // processing it
-    // TODO: Investigate if there is a more performant way to handle
-    // incoming chunks
-    // see: https://github.com/nodejs/undici/issues/2630
-    if (this.buffer) {
-      this.buffer = Buffer.concat([this.buffer, chunk])
-    } else {
-      this.buffer = chunk
-    }
+    this.chunks.push(chunk)
 
     // Strip leading byte-order-mark if we opened the stream and started
     // the processing of the incoming data
     if (this.checkBOM) {
-      switch (this.buffer.length) {
-        case 1:
-          // Check if the first byte is the same as the first byte of the BOM
-          if (this.buffer[0] === BOM[0]) {
-            // If it is, we need to wait for more data
-            callback()
-            return
-          }
-          // Set the checkBOM flag to false as we don't need to check for the
-          // BOM anymore
-          this.checkBOM = false
-
-          // The buffer only contains one byte so we need to wait for more data
-          callback()
-          return
-        case 2:
-          // Check if the first two bytes are the same as the first two bytes
-          // of the BOM
-          if (
-            this.buffer[0] === BOM[0] &&
-            this.buffer[1] === BOM[1]
-          ) {
-            // If it is, we need to wait for more data, because the third byte
-            // is needed to determine if it is the BOM or not
-            callback()
-            return
-          }
-
-          // Set the checkBOM flag to false as we don't need to check for the
-          // BOM anymore
-          this.checkBOM = false
-          break
-        case 3:
-          // Check if the first three bytes are the same as the first three
-          // bytes of the BOM
-          if (
-            this.buffer[0] === BOM[0] &&
-            this.buffer[1] === BOM[1] &&
-            this.buffer[2] === BOM[2]
-          ) {
-            // If it is, we can drop the buffered data, as it is only the BOM
-            this.buffer = Buffer.alloc(0)
-            // Set the checkBOM flag to false as we don't need to check for the
-            // BOM anymore
-            this.checkBOM = false
-
-            // Await more data
-            callback()
-            return
-          }
-          // If it is not the BOM, we can start processing the data
-          this.checkBOM = false
-          break
-        default:
-          // The buffer is longer than 3 bytes, so we can drop the BOM if it is
-          // present
-          if (
-            this.buffer[0] === BOM[0] &&
-            this.buffer[1] === BOM[1] &&
-            this.buffer[2] === BOM[2]
-          ) {
-            // Remove the BOM from the buffer
-            this.buffer = this.buffer.subarray(3)
-          }
-
-          // Set the checkBOM flag to false as we don't need to check for the
-          this.checkBOM = false
-          break
+      if (this.handleBOM()) {
+        callback()
+        return
       }
     }
 
-    while (this.pos < this.buffer.length) {
+    while (this.hasCurrentByte()) {
+      const byte = this.currentByte()
+
       // If the previous line ended with an end-of-line, we need to check
       // if the next character is also an end-of-line.
       if (this.eventEndCheck) {
@@ -17642,10 +17906,9 @@ class EventSourceStream extends Transform {
         if (this.crlfCheck) {
           // If the current character is a line feed, we can remove it
           // from the buffer and reset the crlfCheck flag
-          if (this.buffer[this.pos] === LF) {
-            this.buffer = this.buffer.subarray(this.pos + 1)
-            this.pos = 0
+          if (byte === LF) {
             this.crlfCheck = false
+            this.consumeCurrentByte()
 
             // It is possible that the line feed is not the end of the
             // event. We need to check if the next character is an
@@ -17661,19 +17924,17 @@ class EventSourceStream extends Transform {
           this.crlfCheck = false
         }
 
-        if (this.buffer[this.pos] === LF || this.buffer[this.pos] === CR) {
+        if (byte === LF || byte === CR) {
           // If the current character is a carriage return, we need to
           // set the crlfCheck flag to true, as we need to check if the
           // next character is a line feed so we can remove it from the
           // buffer
-          if (this.buffer[this.pos] === CR) {
+          if (byte === CR) {
             this.crlfCheck = true
           }
 
-          this.buffer = this.buffer.subarray(this.pos + 1)
-          this.pos = 0
-          if (
-            this.event.data !== undefined || this.event.event || this.event.id || this.event.retry) {
+          this.consumeCurrentByte()
+          if (this.hasPendingEvent()) {
             this.processEvent(this.event)
           }
           this.clearEvent()
@@ -17687,22 +17948,18 @@ class EventSourceStream extends Transform {
 
       // If the current character is an end-of-line, we can process the
       // line
-      if (this.buffer[this.pos] === LF || this.buffer[this.pos] === CR) {
+      if (byte === LF || byte === CR) {
         // If the current character is a carriage return, we need to
         // set the crlfCheck flag to true, as we need to check if the
         // next character is a line feed
-        if (this.buffer[this.pos] === CR) {
+        if (byte === CR) {
           this.crlfCheck = true
         }
 
         // In any case, we can process the line as we reached an
         // end-of-line character
-        this.parseLine(this.buffer.subarray(0, this.pos), this.event)
-
-        // Remove the processed line from the buffer
-        this.buffer = this.buffer.subarray(this.pos + 1)
-        // Reset the position as we removed the processed line from the buffer
-        this.pos = 0
+        this.parseLine(this.readLine(), this.event)
+        this.consumeCurrentByte()
         // A line was processed and this could be the end of the event. We need
         // to check if the next line is empty to determine if the event is
         // finished.
@@ -17710,7 +17967,7 @@ class EventSourceStream extends Transform {
         continue
       }
 
-      this.pos++
+      this.advanceCursor()
     }
 
     callback()
@@ -17735,64 +17992,53 @@ class EventSourceStream extends Transform {
       return
     }
 
-    let field = ''
-    let value = ''
+    let fieldLength = line.length
+    let valueStart = line.length
 
     // If the line contains a U+003A COLON character (:)
     if (colonPosition !== -1) {
-      // Collect the characters on the line before the first U+003A COLON
-      // character (:), and let field be that string.
-      // TODO: Investigate if there is a more performant way to extract the
-      // field
-      // see: https://github.com/nodejs/undici/issues/2630
-      field = line.subarray(0, colonPosition).toString('utf8')
+      fieldLength = colonPosition
 
       // Collect the characters on the line after the first U+003A COLON
       // character (:), and let value be that string.
       // If value starts with a U+0020 SPACE character, remove it from value.
-      let valueStart = colonPosition + 1
+      valueStart = colonPosition + 1
       if (line[valueStart] === SPACE) {
         ++valueStart
       }
-      // TODO: Investigate if there is a more performant way to extract the
-      // value
-      // see: https://github.com/nodejs/undici/issues/2630
-      value = line.subarray(valueStart).toString('utf8')
-
-      // Otherwise, the string is not empty but does not contain a U+003A COLON
-      // character (:)
-    } else {
-      // Process the field using the steps described below, using the whole
-      // line as the field name, and the empty string as the field value.
-      field = line.toString('utf8')
-      value = ''
     }
 
-    // Modify the event with the field name and value. The value is also
-    // decoded as UTF-8
-    switch (field) {
-      case 'data':
-        if (event[field] === undefined) {
-          event[field] = value
-        } else {
-          event[field] += `\n${value}`
-        }
-        break
-      case 'retry':
-        if (isASCIINumber(value)) {
-          event[field] = value
-        }
-        break
-      case 'id':
-        if (isValidLastEventId(value)) {
-          event[field] = value
-        }
-        break
-      case 'event':
-        if (value.length > 0) {
-          event[field] = value
-        }
-        break
+    if (isFieldName(line, fieldLength, DATA)) {
+      const value = line.toString('utf8', valueStart)
+
+      if (event.data === undefined) {
+        event.data = value
+      } else {
+        event.data += `\n${value}`
+      }
+      return
+    }
+
+    if (isFieldName(line, fieldLength, RETRY)) {
+      if (isASCIINumberBytes(line, valueStart)) {
+        event.retry = line.toString('utf8', valueStart)
+      }
+      return
+    }
+
+    if (isFieldName(line, fieldLength, ID)) {
+      if (isValidLastEventIdBytes(line, valueStart)) {
+        event.id = line.toString('utf8', valueStart)
+      }
+      return
+    }
+
+    if (isFieldName(line, fieldLength, EVENT)) {
+      const value = line.toString('utf8', valueStart)
+
+      if (value.length > 0) {
+        event.event = value
+      }
     }
   }
 
@@ -17822,13 +18068,152 @@ class EventSourceStream extends Transform {
   }
 
   clearEvent () {
-    this.event = {
-      data: undefined,
-      event: undefined,
-      id: undefined,
-      retry: undefined
+    this.event.data = undefined
+    this.event.event = undefined
+    this.event.id = undefined
+    this.event.retry = undefined
+  }
+
+  hasPendingEvent () {
+    return this.event.data !== undefined ||
+      this.event.event !== undefined ||
+      this.event.id !== undefined ||
+      this.event.retry !== undefined
+  }
+
+  hasCurrentByte () {
+    return this.chunkIndex < this.chunks.length &&
+      this.pos < this.chunks[this.chunkIndex].length
+  }
+
+  currentByte () {
+    return this.chunks[this.chunkIndex][this.pos]
+  }
+
+  consumeCurrentByte () {
+    this.advanceCursor()
+    this.syncLineStartToCursor()
+  }
+
+  advanceCursor () {
+    this.pos++
+
+    while (this.chunkIndex < this.chunks.length && this.pos >= this.chunks[this.chunkIndex].length) {
+      this.chunkIndex++
+      this.pos = 0
     }
   }
+
+  syncLineStartToCursor () {
+    this.lineChunkIndex = this.chunkIndex
+    this.linePos = this.pos
+    this.dropConsumedChunks()
+  }
+
+  dropConsumedChunks () {
+    while (this.lineChunkIndex > 0) {
+      this.chunks.shift()
+      this.lineChunkIndex--
+      this.chunkIndex--
+    }
+
+    if (this.chunkIndex === this.chunks.length) {
+      this.chunks.length = 0
+      this.chunkIndex = 0
+      this.pos = 0
+      this.lineChunkIndex = 0
+      this.linePos = 0
+    }
+  }
+
+  readLine () {
+    if (this.lineChunkIndex === this.chunkIndex) {
+      return this.chunks[this.chunkIndex].subarray(this.linePos, this.pos)
+    }
+
+    const chunks = []
+    let length = 0
+
+    for (let i = this.lineChunkIndex; i <= this.chunkIndex; i++) {
+      const chunk = this.chunks[i]
+      const start = i === this.lineChunkIndex ? this.linePos : 0
+      const end = i === this.chunkIndex ? this.pos : chunk.length
+      const slice = chunk.subarray(start, end)
+      length += slice.length
+      chunks.push(slice)
+    }
+
+    return Buffer.concat(chunks, length)
+  }
+
+  peekBufferedByte (offset) {
+    let chunkIndex = this.lineChunkIndex
+    let pos = this.linePos
+
+    while (chunkIndex < this.chunks.length) {
+      const chunk = this.chunks[chunkIndex]
+      const remaining = chunk.length - pos
+
+      if (offset < remaining) {
+        return chunk[pos + offset]
+      }
+
+      offset -= remaining
+      chunkIndex++
+      pos = 0
+    }
+  }
+
+  discardLeadingBytes (count) {
+    while (count > 0 && this.lineChunkIndex < this.chunks.length) {
+      const chunk = this.chunks[this.lineChunkIndex]
+      const remaining = chunk.length - this.linePos
+
+      if (count < remaining) {
+        this.linePos += count
+        count = 0
+      } else {
+        count -= remaining
+        this.lineChunkIndex++
+        this.linePos = 0
+      }
+    }
+
+    this.chunkIndex = this.lineChunkIndex
+    this.pos = this.linePos
+    this.dropConsumedChunks()
+  }
+
+  handleBOM () {
+    const first = this.peekBufferedByte(0)
+    const second = this.peekBufferedByte(1)
+    const third = this.peekBufferedByte(2)
+
+    if (second === undefined) {
+      if (first === BOM[0]) {
+        return true
+      }
+
+      this.checkBOM = false
+      return true
+    }
+
+    if (third === undefined) {
+      if (first === BOM[0] && second === BOM[1]) {
+        return true
+      }
+
+      this.checkBOM = false
+      return false
+    }
+
+    if (first === BOM[0] && second === BOM[1] && third === BOM[2]) {
+      this.discardLeadingBytes(3)
+    }
+
+    this.checkBOM = false
+    return !this.hasCurrentByte()
+  }
 }
 
 module.exports = {
@@ -29096,7 +29481,7 @@ function establishWebSocketConnection (url, protocols, client, ws, onEstablish,
         // is specified, the server needs to include the same field and one of
         // the selected subprotocol values in its response for the connection to
         // be established.
-        if (!requestProtocols.includes(secProtocol)) {
+        if (requestProtocols === null || !requestProtocols.includes(secProtocol)) {
           failWebsocketConnection(ws, 'Protocol was not set in the opening handshake.')
           return
         }
@@ -29857,7 +30242,12 @@ class PerMessageDeflate {
 
         if (this.#maxPayloadSize > 0 && this.#inflate[kLength] > this.#maxPayloadSize) {
           callback(new MessageSizeExceededError())
+          // The inflater may still hold buffered input that can emit a late
+          // zlib error. Remove the data listener, then deterministically stop
+          // the stream so a subsequent 'error' cannot fire without a listener
+          // (which would terminate the process as an unhandled error event).
           this.#inflate.removeAllListeners()
+          this.#inflate.destroy()
           this.#inflate = null
           return
         }