[Security] Bump undici and discord.js

Dependabotrequested to merge
dependabot-npm_and_yarn-multi-d1cf14a530 into master

Bumps undici to 6.27.0 and updates ancestor dependency discord.js. These dependencies need to be updated together.

Updates undici from 5.29.0 to 6.27.0 This update includes security fixes.

Vulnerabilities fixed

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

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

Patched versions: 6.23.0; 7.18.2 Affected versions: < 6.23.0; >= 7.0.0, < 7.18.2

Undici has an HTTP Request/Response Smuggling issue

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:

... (truncated)

Patched versions: 7.24.0; 6.24.0 Affected versions: >= 7.0.0, < 7.24.0; < 6.24.0

Undici has CRLF Injection in undici via upgrade option

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.

... (truncated)

Patched versions: 7.24.0; 6.24.0 Affected versions: >= 7.0.0, < 7.24.0; < 6.24.0

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

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?

Patched versions: 7.24.0; 6.24.0 Affected versions: >= 7.0.0, < 7.24.0; < 6.24.0

Undici has Unbounded Memory Consumption in WebSocket permessage-deflate Decompression

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.

Patched versions: 7.24.0; 6.24.0 Affected versions: >= 7.0.0, < 7.24.0; < 6.24.0

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

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.

Patched versions: 8.5.0; 7.28.0; 6.27.0 Affected versions: >= 8.0.0, < 8.5.0; >= 7.0.0, < 7.28.0; < 6.27.0

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

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.

Patched versions: 8.5.0; 7.28.0; 6.27.0 Affected versions: >= 8.0.0, < 8.5.0; >= 7.0.0, < 7.28.0; < 6.27.0

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

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.

Patched versions: 8.5.0; 7.28.0; 6.27.0 Affected versions: >= 8.0.0, < 8.5.0; >= 7.0.0, < 7.28.0; < 6.27.0

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

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.

Patched versions: 8.5.0; 7.28.0; 6.27.0 Affected versions: >= 8.0.0, < 8.5.0; >= 7.0.0, < 7.28.0; < 6.27.0

Release notes

Sourced from undici's releases.

v6.27.0

⚠️ Security Release

This release line addresses 4 security advisories.

Action required: Upgrade to undici 6.27.0 or later.

npm install undici@^6.27.0

Note on patched version: the v6 fixes shipped in v6.27.0, not 6.26.0 — v6.26.0 contains only the chunked-EOF fix (#5308) and the version bump, none of the security fixes below.

The v6 line is not affected by the SOCKS5 advisories (GHSA-vmh5-mc38-953g, GHSA-hm92-r4w5-c3mj), the shared-cache disclosure (GHSA-pr7r-676h-xcf6), or the 8.x-only WebSocket regression (GHSA-38rv-x7px-6hhq).

Summary

Advisory CVE Severity (CVSS) Fixed in Fix commit
GHSA-vxpw-j846-p89q CVE-2026-12151 High (7.5) 6.27.0 b7f252e7
GHSA-p88m-4jfj-68fv CVE-2026-9679 Moderate (5.9) 6.27.0 25efa447
GHSA-g8m3-5g58-fq7m CVE-2026-11525 Low (3.7) 6.27.0 25efa447
GHSA-35p6-xmwp-9g52 CVE-2026-6733 Low (3.7) 6.27.0 f4c31d60

High severity

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

GHSA-vxpw-j846-p89q · CWE-400, CWE-770 Fix: b7f252e7 Backport WebSocket maxPayloadSize fixes (#5423, backported to v6 in #5428)

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. All releases from 6.17.0 onward are affected.

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

Moderate severity

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

... (truncated)

Commits
Maintainer changes

This version was pushed to npm by GitHub Actions, a new releaser for undici since your current version.

Install script changes

This version modifies prepare script that runs during installation. Review the package contents before updating.


Updates discord.js from 14.3.0 to 14.27.0

Release notes

Sourced from discord.js's releases.

14.27.0

Bug Fixes

Documentation

Features

Refactor

Typings

  • WebhookMessageCreateOptions: Omit sharedClientTheme (b816b79)
  • Message: Specify rawData arg type (#11123) (c4531d4)
  • UserManager: Fix send() return type to Promise<Message> (#11337) (07c4127)

14.26.5

Bug Fixes

14.26.4

Bug Fixes

  • MessageCreateAction: Receive DMs in uncached DMChannels again (#11495) (b8d8812)

... (truncated)

Changelog

Sourced from discord.js's changelog.

14.27.0 - (2026-07-15)

Bug Fixes

Documentation

Features

Refactor

Typings

  • WebhookMessageCreateOptions: Omit sharedClientTheme (b816b79)
  • Message: Specify rawData arg type (#11123) (c4531d4)
  • UserManager: Fix send() return type to Promise<Message> (#11337) (07c4127)

14.26.5 - (2026-07-10)

Bug Fixes

14.26.4 - (2026-05-01)

... (truncated)

Commits
Maintainer changes

This version was pushed to npm by crawl, a new releaser for discord.js since your current version.


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