fix(deps): update dependency undici to v8 [security]

[renovate]

ℹ️ Note

This PR body was truncated due to platform limits.

This PR contains the following updates:

Package	Change	Age	Confidence
undici (source)	^5.14.0 → ^8.0.0

---

Undici has an unbounded decompression chain in HTTP responses on Node.js Fetch API via Content-Encoding leads to resource exhaustion

CVE-2026-22036 / GHSA-g9mf-h72j-4rw9

More information

Details

Impact

The fetch() API supports chained HTTP encoding algorithms for response content according to RFC 9110 (e.g., Content-Encoding: gzip, br). This is also supported by the undici decompress interceptor.

However, the number of links in the decompression chain is unbounded and the default maxHeaderSize allows a malicious server to insert thousands compression steps leading to high CPU usage and excessive memory allocation.

Patches

Upgrade to 7.18.2 or 6.23.0.

Workarounds

It is possible to apply an undici interceptor and filter long Content-Encoding sequences manually.

References

• https://hackerone.com/reports/3456148
• GHSA-gm62-xv2j-4w53
• https://curl.se/docs/CVE-2022-32206.html

Severity

• CVSS Score: 5.9 / 10 (Medium)
• Vector String: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

References

• https://github.com/nodejs/undici/security/advisories/GHSA-g9mf-h72j-4rw9
• https://github.com/nodejs/undici/commit/b04e3cbb569c1596f86c108e9b52c79d8475dcb3
• https://nvd.nist.gov/vuln/detail/CVE-2026-22036
• https://github.com/advisories/GHSA-g9mf-h72j-4rw9

This data is provided by the GitHub Advisory Database (CC-BY 4.0).

---

Undici has an HTTP Request/Response Smuggling issue

CVE-2026-1525 / GHSA-2mjp-6q6p-2qxm

More information

Details

Impact

Undici allows duplicate HTTP Content-Length headers when they are provided in an array with case-variant names (e.g., Content-Length and content-length). This produces malformed HTTP/1.1 requests with multiple conflicting Content-Length values on the wire.

Who is impacted:

• Applications using undici.request(), undici.Client, or similar low-level APIs with headers passed as flat arrays
• Applications that accept user-controlled header names without case-normalization

Potential consequences:

• Denial of Service: Strict HTTP parsers (proxies, servers) will reject requests with duplicate Content-Length headers (400 Bad Request)
• HTTP Request Smuggling: In deployments where an intermediary and backend interpret duplicate headers inconsistently (e.g., one uses the first value, the other uses the last), this can enable request smuggling attacks leading to ACL bypass, cache poisoning, or credential hijacking

Patches

Patched in the undici version v7.24.0 and v6.24.0. Users should upgrade to this version or later.

Workarounds

If upgrading is not immediately possible:

1. Validate header names: Ensure no duplicate Content-Length headers (case-insensitive) are present before passing headers to undici
2. Use object format: Pass headers as a plain object ({ 'content-length': '123' }) rather than an array, which naturally deduplicates by key
3. Sanitize user input: If headers originate from user input, normalize header names to lowercase and reject duplicates

Severity

• CVSS Score: 6.5 / 10 (Medium)
• Vector String: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L

References

• https://github.com/nodejs/undici/security/advisories/GHSA-2mjp-6q6p-2qxm
• https://nvd.nist.gov/vuln/detail/CVE-2026-1525
• https://hackerone.com/reports/3556037
• https://cna.openjsf.org/security-advisories.html
• https://cwe.mitre.org/data/definitions/444.html
• https://www.rfc-editor.org/rfc/rfc9110.html#section-8.6
• https://github.com/advisories/GHSA-2mjp-6q6p-2qxm

This data is provided by the GitHub Advisory Database (CC-BY 4.0).

---

Undici has Unbounded Memory Consumption in WebSocket permessage-deflate Decompression

CVE-2026-1526 / GHSA-vrm6-8vpv-qv8q

More information

Details

Description

The undici WebSocket client is vulnerable to a denial-of-service attack via unbounded memory consumption during permessage-deflate decompression. When a WebSocket connection negotiates the permessage-deflate extension, the client decompresses incoming compressed frames without enforcing any limit on the decompressed data size. A malicious WebSocket server can send a small compressed frame (a "decompression bomb") that expands to an extremely large size in memory, causing the Node.js process to exhaust available memory and crash or become unresponsive.

The vulnerability exists in the PerMessageDeflate.decompress() method, which accumulates all decompressed chunks in memory and concatenates them into a single Buffer without checking whether the total size exceeds a safe threshold.

Impact

• Remote denial of service against any Node.js application using undici's WebSocket client
• A single compressed WebSocket frame of ~6 MB can decompress to ~1 GB or more
• Memory exhaustion occurs in native/external memory, bypassing V8 heap limits
• No application-level mitigation is possible as decompression occurs before message delivery

Patches

Users should upgrade to fixed versions.

Workarounds

No workaround are possible.

Severity

• CVSS Score: 7.5 / 10 (High)
• Vector String: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

References

• https://github.com/nodejs/undici/security/advisories/GHSA-vrm6-8vpv-qv8q
• https://nvd.nist.gov/vuln/detail/CVE-2026-1526
• https://hackerone.com/reports/3481206
• https://cna.openjsf.org/security-advisories.html
• https://datatracker.ietf.org/doc/html/rfc7692
• https://owasp.org/www-community/attacks/Denial_of_Service
• https://github.com/advisories/GHSA-vrm6-8vpv-qv8q

This data is provided by the GitHub Advisory Database (CC-BY 4.0).

---

Undici has Unhandled Exception in WebSocket Client Due to Invalid server_max_window_bits Validation

CVE-2026-2229 / GHSA-v9p9-hfj2-hcw8

More information

Details

Impact

The undici WebSocket client is vulnerable to a denial-of-service attack due to improper validation of the server_max_window_bits parameter in the permessage-deflate extension. When a WebSocket client connects to a server, it automatically advertises support for permessage-deflate compression. A malicious server can respond with an out-of-range server_max_window_bits value (outside zlib's valid range of 8-15). When the server subsequently sends a compressed frame, the client attempts to create a zlib InflateRaw instance with the invalid windowBits value, causing a synchronous RangeError exception that is not caught, resulting in immediate process termination.

The vulnerability exists because:

1. The isValidClientWindowBits() function only validates that the value contains ASCII digits, not that it falls within the valid range 8-15
2. The createInflateRaw() call is not wrapped in a try-catch block
3. The resulting exception propagates up through the call stack and crashes the Node.js process

Patches

Has the problem been patched? What versions should users upgrade to?

Workarounds

Is there a way for users to fix or remediate the vulnerability without upgrading?

Severity

• CVSS Score: 7.5 / 10 (High)
• Vector String: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

References

• https://github.com/nodejs/undici/security/advisories/GHSA-v9p9-hfj2-hcw8
• https://nvd.nist.gov/vuln/detail/CVE-2026-2229
• https://hackerone.com/reports/3487486
• https://cna.openjsf.org/security-advisories.html
• https://datatracker.ietf.org/doc/html/rfc7692
• https://nodejs.org/api/zlib.html#class-zlibinflateraw
• https://github.com/advisories/GHSA-v9p9-hfj2-hcw8

This data is provided by the GitHub Advisory Database (CC-BY 4.0).

---

Undici has CRLF Injection in undici via upgrade option

CVE-2026-1527 / GHSA-4992-7rv2-5pvq

More information

Details

Impact

When an application passes user-controlled input to the upgrade option of client.request(), an attacker can inject CRLF sequences (\r\n) to:

1. Inject arbitrary HTTP headers
2. Terminate the HTTP request prematurely and smuggle raw data to non-HTTP services (Redis, Memcached, Elasticsearch)

The vulnerability exists because undici writes the upgrade value directly to the socket without validating for invalid header characters:

// lib/dispatcher/client-h1.js:1121
if (upgrade) {
  header += `connection: upgrade\r\nupgrade: ${upgrade}\r\n`
}

Patches

Patched in the undici version v7.24.0 and v6.24.0. Users should upgrade to this version or later.

Workarounds

Sanitize the upgrade option string before passing to undici:

function sanitizeUpgrade(value) {
  if (/[\r\n]/.test(value)) {
    throw new Error('Invalid upgrade value')
  }
  return value
}

client.request({
  upgrade: sanitizeUpgrade(userInput)
})

Severity

• CVSS Score: 4.6 / 10 (Medium)
• Vector String: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:N

References

• https://github.com/nodejs/undici/security/advisories/GHSA-4992-7rv2-5pvq
• https://nvd.nist.gov/vuln/detail/CVE-2026-1527
• https://hackerone.com/reports/3487198
• https://cna.openjsf.org/security-advisories.html
• https://github.com/advisories/GHSA-4992-7rv2-5pvq

This data is provided by the GitHub Advisory Database (CC-BY 4.0).

---

undici WebSocket client vulnerable to denial of service via fragment count bypass

CVE-2026-12151 / GHSA-vxpw-j846-p89q

More information

Details

Impact

The undici WebSocket client enforces maxPayloadSize on the cumulative byte count of fragments in a message but does not enforce a limit on the number of fragments. A malicious WebSocket server can stream many small or empty continuation frames that each pass per-frame and cumulative-size validation, collectively causing unbounded memory growth in the client process. The result is memory exhaustion and a denial of service.

Affected applications are those using the undici WebSocket client (new WebSocket(...)) or the WebSocketStream API that can be induced to connect to an attacker-controlled or compromised WebSocket endpoint.

All releases starting at undici 6.17.0 are affected.

Patches

Upgrade to undici v6.27.0, v7.28.0 or v8.5.0.

Workarounds

No workaround is available. The fix must be applied through an upgrade.

Severity

• CVSS Score: 7.5 / 10 (High)
• Vector String: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

References

• https://github.com/nodejs/undici/security/advisories/GHSA-vxpw-j846-p89q
• https://nvd.nist.gov/vuln/detail/CVE-2026-12151
• https://cna.openjsf.org/security-advisories.html
• https://github.com/advisories/GHSA-vxpw-j846-p89q

This data is provided by the GitHub Advisory Database (CC-BY 4.0).

---

undici vulnerable to HTTP response queue poisoning via keep-alive socket reuse

CVE-2026-6733 / GHSA-35p6-xmwp-9g52

More information

Details

Impact

Undici's HTTP/1.1 client is vulnerable to response queue poisoning on reused keep-alive sockets. An attacker-controlled upstream server can inject an unsolicited HTTP/1.1 response onto an idle socket after a request completes. When the client dispatches the next request on that socket, it associates the injected response with the new request, causing responses to be delivered to the wrong requests.

This requires an attacker-controlled or compromised upstream HTTP/1.1 server and keep-alive connection reuse.

Patches

Upgrade to undici v6.27.0, v7.28.0 or v8.5.0.

Workarounds

Disable keep-alive connection reuse by setting keepAliveTimeout: 0 on the Client or Pool.

Severity

• CVSS Score: 3.7 / 10 (Low)
• Vector String: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N

References

• https://github.com/nodejs/undici/security/advisories/GHSA-35p6-xmwp-9g52
• https://nvd.nist.gov/vuln/detail/CVE-2026-6733
• https://hackerone.com/reports/3582376
• https://cna.openjsf.org/security-advisories.html
• https://github.com/advisories/GHSA-35p6-xmwp-9g52

This data is provided by the GitHub Advisory Database (CC-BY 4.0).

---

undici vulnerable to HTTP header injection via Set-Cookie percent-decoding

CVE-2026-9679 / GHSA-p88m-4jfj-68fv

More information

Details

Impact

undici's cookie parser in parseSetCookie percent-decodes cookie values via qsUnescape, turning encoded sequences like %0D%0A, %00, %3B, and %3D into their literal byte equivalents. RFC 6265 §5.4 does not specify any decoding and browsers do not decode either.

Applications that parse a Set-Cookie header and then forward the parsed value into a response header (proxies, middleware, SSR frameworks) become vulnerable to HTTP response header injection: an attacker-controlled upstream can inject arbitrary Set-Cookie, Location, or Cache-Control headers into the application's downstream response, enabling session fixation, open redirect, or cache poisoning.

Affected applications are those that use undici's cookie parsing (parseSetCookie, parseCookie, getSetCookies) and forward the parsed cookie value into a response header.

This was introduced in undici 7.0.0 via #​3789.

Patches

Upgrade to undici v6.27.0, v7.28.0 or v8.5.0.

Workarounds

If upgrade is not immediately possible, do not forward values returned by parseSetCookie/parseCookie/getSetCookies directly into response headers; sanitize the value first to strip or reject CR, LF, NUL, ;, and = bytes.

Severity

• CVSS Score: 5.9 / 10 (Medium)
• Vector String: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N

References

• https://github.com/nodejs/undici/security/advisories/GHSA-p88m-4jfj-68fv
• https://nvd.nist.gov/vuln/detail/CVE-2026-9679
• https://cna.openjsf.org/security-advisories.html
• https://github.com/advisories/GHSA-p88m-4jfj-68fv

This data is provided by the GitHub Advisory Database (CC-BY 4.0).

---

undici vulnerable to Set-Cookie SameSite attribute downgrade via permissive substring matching

CVE-2026-11525 / GHSA-g8m3-5g58-fq7m

More information

Details

Impact

When undici parses a Set-Cookie header, it accepts any SameSite attribute value that contains Strict, Lax, or None as a substring, rather than the case-insensitive exact match specified by RFC 6265. Non-spec values are silently mapped to one of the three standard tokens:

• SameSite=NoneOfYourBusiness is parsed as None, the most permissive setting.
• SameSite=StrictLax is parsed as Lax, a downgrade from Strict.

Affected applications are those that consume Set-Cookie headers from server responses (for example via undici's fetch or proxy code paths) and then forward or rely on the parsed sameSite attribute. A malicious or non-compliant server can coerce the consumer's view of a cookie's SameSite policy to a weaker value, silently degrading the SameSite enforcement the cookie is supposed to provide.

This was introduced in undici 5.15.0 when the cookies feature was added.

Patches

Upgrade to undici v6.27.0, v7.28.0 or v8.5.0.

Workarounds

After parsing a Set-Cookie header, validate that the resulting sameSite attribute is one of 'Strict', 'Lax', or 'None' (exact, case-insensitive) before forwarding or relying on it.

Severity

• CVSS Score: 3.7 / 10 (Low)
• Vector String: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N

References

• https://github.com/nodejs/undici/security/advisories/GHSA-g8m3-5g58-fq7m
• https://nvd.nist.gov/vuln/detail/CVE-2026-11525
• https://cna.openjsf.org/security-advisories.html
• https://github.com/advisories/GHSA-g8m3-5g58-fq7m

This data is provided by the GitHub Advisory Database (CC-BY 4.0).

---

Release Notes

nodejs/undici (undici)

v8.7.0

Compare Source

What's Changed

• test: guard balanced-pool error port lookup by @​mcollina in #​5463
• perf: optimize http/2 request hot path by @​mcollina in #​5483
• fix: do not reject open-ended Range values in simpleRangeHeaderValue by @​spokodev in #​5490
• fix(eventsource): set use-URL-credentials flag by @​Ram-blip in #​5489
• test: deflake connect-timeout watchdog by @​mcollina in #​5197
• docs: correct npm script name and JSON syntax in examples by @​lenoxfernando in #​5496
• fix: reject non-ascii octets in validateCookiePath by @​spokodev in #​5452
• fix(readable): ignore late consume chunks by @​marko1olo in #​5375
• fix(h2): destroy the stream on abort instead of relying on close() by @​staylor in #​5462
• fix: ignore an unparseable Set-Cookie Expires attribute by @​spokodev in #​5488
• docs: add reproduction guide and update bug report template by @​mcollina in #​5451
• fix(h2): guard onResponse against a 'response' event delivered after completion by @​staylor in #​5440
• fix(h2): requeue request on GOAWAY'd session instead of crashing by @​staylor in #​5453
• fix: add static buildDispatch method to RedirectHandler type definition by @​matthieusieben in #​5442
• fix: auto-detect HTTP proxy tunneling by @​mcollina in #​5116

New Contributors

• @​spokodev made their first contribution in #​5490
• @​lenoxfernando made their first contribution in #​5496
• @​staylor made their first contribution in #​5462

Full Changelog: nodejs/undici@v8.6.0...v8.7.0

v8.6.0

Compare Source

v8.5.0

Compare Source

⚠️ Security Release

This release line addresses 8 security advisories. Most are fixed in
v8.5.0; the SOCKS5 pool-reuse issue was fixed earlier in v8.2.0.

Action required: Upgrade to undici 8.5.0 or later.

npm install undici@^8.5.0

Summary

Advisory	CVE	Severity (CVSS)	Fixed in	Fix commit
GHSA-vxpw-j846-p89q	CVE-2026-12151	High (7.5)	8.5.0	32dbf0b3
GHSA-38rv-x7px-6hhq	CVE-2026-9675	High (7.5)	8.5.0	b4c287b3
GHSA-vmh5-mc38-953g	CVE-2026-9697	High (7.4)	8.5.0	42d49559
GHSA-hm92-r4w5-c3mj	CVE-2026-6734	High (7.5)	8.2.0	a516f870
GHSA-pr7r-676h-xcf6	CVE-2026-9678	Moderate (5.9)	8.5.0	cb105d7c
GHSA-p88m-4jfj-68fv	CVE-2026-9679	Moderate (5.9)	8.5.0	5655ea43
GHSA-g8m3-5g58-fq7m	CVE-2026-11525	Low (3.7)	8.5.0	5655ea43
GHSA-35p6-xmwp-9g52	CVE-2026-6733	Low (3.7)	8.5.0	6ea54ef8

---

High severity

WebSocket DoS via fragment count bypass — CVE-2026-12151

GHSA-vxpw-j846-p89q · CWE-400, CWE-770
Fix: 32dbf0b3 websocket: limit the number of fragments in a message (also c5ed7875 handle empty fragments and stream limits)

A malicious WebSocket server can stream a large number of small or empty
continuation frames. Undici enforced a limit on cumulative payload size but did
not limit the number of fragments per message, leading to unbounded memory
growth and denial of service.

• Affected: applications using new WebSocket(...) or WebSocketStream
  against untrusted endpoints.
• Workaround: none — upgrade is required.

WebSocket DoS via cumulative fragment bypass — CVE-2026-9675

GHSA-38rv-x7px-6hhq · CWE-400, CWE-770
Fix: b4c287b3 fix(websocket): enforce max payload size across fragments

Undici validated the size of individual frames but did not track cumulative size
across a fragmented message. An attacker could send many small fragments that
each pass per-frame validation but collectively exceed the configured limit,
causing memory exhaustion. This is a regression introduced in 8.1.0 (the
6.x and 7.x lines are not affected).

• Workaround: none — upgrade is required.

TLS certificate validation bypass in SOCKS5 ProxyAgent — CVE-2026-9697

GHSA-vmh5-mc38-953g · CWE-295
Fix: 42d49559 fix: honor requestTls when proxy is SOCKS5

The ProxyAgent silently discarded the requestTls option when configured with
a SOCKS5 proxy. TLS connections through the SOCKS5 tunnel ignored user-configured
parameters such as ca, cert, key, rejectUnauthorized, and servername,
falling back to the default Mozilla CA bundle. Applications relying on
certificate pinning to an internal CA were exposed to man-in-the-middle attacks.

• Affected: ProxyAgent / Socks5ProxyAgent over SOCKS5 that rely on
  requestTls.
• Workaround: route traffic through an HTTP-proxy ProxyAgent, where
  requestTls functions correctly.

Cross-origin request routing via SOCKS5 proxy pool reuse — CVE-2026-6734

GHSA-hm92-r4w5-c3mj · CWE-346 · Fixed in 8.2.0
Fix: a516f870 fix(socks5-proxy-agent): use per-origin pools to prevent cross-origin routing (#​5041)

Socks5ProxyAgent reused a single connection pool across different origins
without verifying the pool's origin matched the requested origin. This could
route credentials and request data to unintended destinations, cause responses
from the wrong origin to be trusted, and enable HTTPS→HTTP downgrade.

• Affected: applications using Socks5ProxyAgent across multiple origins
  (introduced via #​4385).
• Workaround: use a separate agent instance per origin.

---

Moderate severity

Cross-user information disclosure via shared cache whitespace bypass — CVE-2026-9678

GHSA-pr7r-676h-xcf6 · CWE-524
Fix: cb105d7c fix(cache): trim qualified field names

The cache interceptor mishandled responses with whitespace-padded
Cache-Control directives such as private=" authorization". In shared-cache
mode this could cause authenticated data to be cached and served to other users.

• Affected: apps using the cache interceptor in shared mode that forward
  Authorization upstream and receive non-canonical qualified directives.
• Workaround: disable shared-cache mode for authenticated traffic, avoid
  caching authenticated responses, or add Vary: Authorization upstream.

HTTP header injection via Set-Cookie percent-decoding — CVE-2026-9679

GHSA-p88m-4jfj-68fv · CWE-93
Fix: 5655ea43 fix(cookies): preserve values and parse SameSite strictly

parseSetCookie applied percent-decoding to cookie values, turning encoded
sequences like %0D%0A and %00 into literal bytes, contrary to RFC 6265 §5.4
and browser behavior. Applications forwarding parsed Set-Cookie values into
response headers were exposed to header injection, enabling session fixation,
open redirects, and cache poisoning. Introduced in 7.0.0 via
#​3789.

• Workaround: sanitize values before forwarding — strip or reject CR, LF,
  NUL, ;, and =.

---

Low severity

Set-Cookie SameSite attribute downgrade — CVE-2026-11525

GHSA-g8m3-5g58-fq7m · CWE-183
Fix: 5655ea43 fix(cookies): preserve values and parse SameSite strictly

The cookie parser accepted SameSite values containing Strict, Lax, or
None as substrings rather than requiring exact matches per RFC 6265. Values
like SameSite=NoneOfYourBusiness parsed as None, and SameSite=StrictLax
parsed as Lax, silently weakening cookie security policies for apps that
forward parsed attributes.

HTTP response queue poisoning via keep-alive socket reuse — CVE-2026-6733

GHSA-35p6-xmwp-9g52 · CWE-367 (TOCTOU race condition)
Fix: 6ea54ef8 fix: guard idle socket validation to skip fresh sockets, hardened by c9fbe9d2 keep idle validation on native timers (#​5397) and ac5394b8 keep idle validation on global timers (#​5407)

An attacker controlling an upstream HTTP/1.1 server could inject unsolicited
responses onto idle keep-alive sockets. On socket reuse, the injected response
was associated with a new request, delivering responses to the wrong requests.

• Requirements: attacker-controlled/compromised upstream and active
  keep-alive reuse.
• Workaround: disable keep-alive reuse with keepAliveTimeout: 0 on the
  Client or Pool.

---

Also in v8.5.0 (non-security)

v8.5.0 shipped the security fixes above alongside the following changes. These
are not security fixes — they are listed for completeness of the release. (The
two queue-poisoning hardening PRs, #​5397
and #​5407, are covered under
CVE-2026-6733 above and are not repeated here.)

• HTTP/2: #5408 don't rewind kPendingIdx past in-flight requests · #5391 allow h2 POST request multiplexing · #5406 reap idle HTTP/2 sessions · #5410 preserve h2 queue on out-of-order completion
• Features: #5416 add bodyMixin.textStream() · #5418 align EventSource with spec
• Docs / CI / tests: #5413 document request header validation · #5383 absorb h2 stream timeout resets (test) · #5420 remove stale repro + lint · #5426 extend Windows CI timeout · #5427 detect available python in WPT runner

Full changelog: v8.4.1...v8.5.0.

---

Credits

Per-advisory credits (as recorded in each GHSA):

• CVE-2026-12151 — reported by @​lpinca & @​Nadav0077; reviewed by @​UlisesGascon.
• CVE-2026-9675 — reported by @​mauriceng98 & @​Str1ckl4nd; fixed by @​mcollina & @​KhafraDev; reviewed by @​UlisesGascon.
• CVE-2026-9697 — reported by @​tonghuaroot; reviewed by @​UlisesGascon.
• CVE-2026-6734 — reported by @​ChALkeR; reviewed by @​mcollina; verified by @​UlisesGascon.
• CVE-2026-9678 — fixed by @​mcollina; reviewed by @​UlisesGascon.
• CVE-2026-9679 — reported by @​tndud042713; fixed by @​mcollina; reviewed by @​KhafraDev & @​UlisesGascon.
• CVE-2026-11525 — fixed by @​mcollina; reviewed by @​UlisesGascon.
• CVE-2026-6733 — fixed by @​mcollina; verified by @​UlisesGascon.

v8.4.1

Compare Source

What's Changed

• test: avoid localhost lookup in fetch cookies tests by @​mcollina in #​5363
• fix: prevent race condition between onEnd and onTrailers in HTTP/2 client (#​5216) by @​mcollina in #​5343
• fix(dns): skip requests without origin by @​marko1olo in #​5376
• docs: add Getting Started guide by @​AliMahmoudDev in #​5371
• docs: fix code examples that crash at runtime and other inaccuracies by @​AliMahmoudDev in #​5386
• fix: handle paused parser on socket end (issue #​5360) by @​mcollina in #​5389
• fix(client): reject pipelined TLS altname errors by @​marko1olo in #​5373
• docs: fix multiple inaccuracies in API documentation by @​AliMahmoudDev in #​5384
• docs: fix remaining broken links in API documentation by @​AliMahmoudDev in #​5342

New Contributors

• @​marko1olo made their first contribution in #​5376

Full Changelog: nodejs/undici@v8.4.0...v8.4.1

v8.4.0

Compare Source

What's Changed

• fix: register connect listener before initiating requests in close-and-destroy test by @​mcollina in #​5272
• test: stabilize tls-cert-leak regression by @​mcollina in #​5306
• fix: replace tspl with native test context in test/examples.js by @​mcollina in #​5300
• http2: remove redundant request stream binding by @​trivikr in #​5302
• test: limit cache-tests workers on Windows by @​mcollina in #​5309
• test: use test context cleanup hooks in parser issue tests by @​mcollina in #​5282
• Add redirect option to strip headers on redirect by @​mcollina in #​5281
• chore(test): fix lint failure by @​aduh95 in #​5316
• chore(ci): use npm ci instead of npm install by @​aduh95 in #​5315
• docs: clarify formData security considerations by @​mcollina in #​5320
• docs: add EventSource server example by @​Will-thom in #​5321
• fix(core): simplify addAbortListener util by @​aduh95 in #​5317
• build(deps-dev): bump ws from 8.20.0 to 8.21.0 by @​dependabot[bot] in #​5325
• build(deps-dev): bump jsondiffpatch from 0.7.3 to 0.7.6 by @​dependabot[bot] in #​5313
• docs: match undici EoL to node version it's bundled in by @​trivikr in #​5330
• fix: handle all HTTP/2 request stream sync errors by @​mcollina in #​5311
• fix: preserve timeout errors for HTTP/2 requests by @​mcollina in #​5091
• fix(core): normalize autoSelectFamily timeout AggregateError by @​youcefzemmar in #​5329
• chore(core): define kEnumerableProperty atomically by @​aduh95 in #​5332
• chore(core): use regex.exec instead of string.match by @​aduh95 in #​5331
• fix: reset invalid HTTP/2 sessions by @​mcollina in #​5310
• feat(connect): add preferH2 connector option to offer h2 first in ALPN by @​Antamansid in #​5327
• test: fix flaky http2 trailers test by @​mcollina in #​5338
• fix(mock): restore single-arg MockCallHistory.filterCallsByX by @​youcefzemmar in #​5328
• docs: document missing error types in Errors.md by @​cesarvspr in #​5339
• build(deps): bump github/codeql-action from 4.35.3 to 4.36.1 by @​dependabot[bot] in #​5346
• build(deps): bump actions/dependency-review-action from 4.9.0 to 5.0.0 by @​dependabot[bot] in #​5347
• build(deps): bump uWebSockets.js from v20.67.0 to v20.68.0 in /benchmarks by @​dependabot[bot] in #​5352
• build(deps): bump concurrently from 9.2.1 to 10.0.3 in /benchmarks by @​dependabot[bot] in #​5353
• build(deps): bump step-security/harden-runner from 2.19.1 to 2.19.4 by @​dependabot[bot] in #​5348
• build(deps): bump actions/checkout from 6.0.2 to 6.0.3 by @​dependabot[bot] in #​5351
• build(deps): bump codecov/codecov-action from 6.0.0 to 6.0.1 by @​dependabot[bot] in #​5349
• docs: improve connect option documentation in Client.md by @​AliMahmoudDev in #​5344
• fix(mock): do not persist snapshots on close in playback mode by @​GeoffreyBooth in #​5359
• fix(fetch): remove abort listener when request settles by @​ATOM00blue in #​5318
• test: add Node.js global fetch regression coverage by @​mcollina in #​5361
• fix(h2): make Client multiplex on h2 (#​4143) by @​mcollina in #​5362

New Contributors

• @​Will-thom made their first contribution in #​5321
• @​youcefzemmar made their first contribution in #​5329
• @​Antamansid made their first contribution in #​5327
• @​cesarvspr made their first contribution in #​5339
• @​AliMahmoudDev made their first contribution in #​5344
• @​ATOM00blue made their first contribution in #​5318

Full Changelog: nodejs/undici@v8.3.0...v8.4.0

v8.3.0

Compare Source

What's Changed

• fix: preserve pool capacity after removing stale client by @​trivikr in #​5151
• build(deps): bump actions/github-script from 8.0.0 to 9.0.0 by @​dependabot[bot] in #​5157
• build(deps): bump actions/upload-artifact from 5.0.0 to 7.0.1 by @​dependabot[bot] in #​5162
• build(deps): bump peter-evans/create-pull-request from 8.1.0 to 8.1.1 by @​dependabot[bot] in #​5156
• chore(http2): collapse duplicate request stream setup by @​trivikr in #​5140
• perf(client): cache HTTP/2 authority by @​trivikr in #​5141
• build(deps-dev): bump borp from 0.20.2 to 1.0.0 by @​dependabot[bot] in #​4819
• types: add TOpaque to client connect options by @​samuel871211 in #​4928
• build(deps): bump tinybench from 5.1.0 to 6.0.1 in /benchmarks by @​dependabot[bot] in #​4688
• build(deps): bump codecov/codecov-action from 5.5.1 to 6.0.0 by @​dependabot[bot] in #​4950
• build(deps): bump actions/dependency-review-action from 4.8.1 to 4.9.0 by @​dependabot[bot] in #​4951
• test(fetch): add userinfo coverage for issue-4897 URLs by @​mcollina in #​4901
• perf: avoid duplicate pool dispatcher selection on backpressure by @​trivikr in #​5149
• build(deps): bump actions/setup-node from 6.2.0 to 6.4.0 by @​dependabot[bot] in #​5163
• build(deps): bump step-security/harden-runner from 2.14.1 to 2.19.1 by @​dependabot[bot] in #​5160
• build(deps): bump cronometro from 5.3.0 to 6.0.3 in /benchmarks by @​dependabot[bot] in #​4687
• build(deps): bump github/codeql-action from 4.35.1 to 4.35.3 by @​dependabot[bot] in #​5161
• build(deps-dev): bump neostandard from 0.12.2 to 0.13.0 by @​dependabot[bot] in #​4853
• build(deps): bump hendrikmuhs/ccache-action from 1.2.22 to 1.2.23 by @​dependabot[bot] in #​5158
• build(deps): bump fastify/github-action-merge-dependabot from 3.11.2 to 3.12.0 by @​dependabot[bot] in #​5159
• build(deps-dev): bump c8 from 10.1.3 to 11.0.0 by @​dependabot[bot] in #​4854
• build(deps): bump uWebSockets.js from v20.64.0 to v20.66.0 in /benchmarks by @​dependabot[bot] in #​5130
• docs: mention install() also installs WebSocket globals by @​mcollina in #​5174
• types: stop interfering with @​types/node by @​Renegade334 in #​5173
• fix: align h2 empty body content-length methods with h1 by @​trivikr in #​5172
• build(deps-dev): bump fast-check from 4.6.0 to 4.7.0 by @​dependabot[bot] in #​5192
• build(deps-dev): bump typescript from 6.0.2 to 6.0.3 by @​dependabot[bot] in #​5191
• test: move cleanup from finally to after hooks by @​trivikr in #​5194
• test: resolve flaky timeout in issue-3356 by @​trivikr in #​5188
• SnapshotAgent: Add normalizeBody and normalizeQuery by @​GeoffreyBooth in #​5121
• fix(socks5): use configured connector in Socks5ProxyAgent by @​trivikr in #​5168
• perf(http2): avoid isArray checks for common headers by @​trivikr in #​5170
• fix(test): make deduplicate body-streaming test non-flaky by @​mcollina in #​5196
• test(retry): add regression test for RetryAgent + HTTP/2 stream timeout (#​5137) by @​mcollina in #​5176
• fix(socks5): preserve dispatch backpressure return value by @​trivikr in #​5166
• perf(http2): end zero-length request bodies with headers by @​trivikr in [#​5169]

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