CVE-2026-12151

NameCVE-2026-12151
DescriptionImpact: 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 >= 6.26.0, >= 7.28.0, or >= 8.5.0. Workarounds: No workaround is available. The fix must be applied through an upgrade.
SourceCVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
node-undici (PTS)bookworm5.15.0+dfsg1+~cs20.10.9.3-1+deb12u4vulnerable
bookworm (security)5.15.0+dfsg1+~cs20.10.9.3-1+deb12u3vulnerable
trixie7.3.0+dfsg1+~cs24.12.11-1vulnerable
forky, sid7.24.6+dfsg+~cs3.2.0-3vulnerable

The information below is based on the following data on fixed versions.

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
node-undicisource(unstable)(unfixed)

Notes

https://github.com/nodejs/undici/security/advisories/GHSA-vxpw-j846-p89q

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