CVE-2026-1526

Name	CVE-2026-1526
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.
Source	CVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)
Debian Bugs	1130880

Vulnerable and fixed packages

The table below lists information on source packages.

Source Package	Release	Version	Status
node-undici (PTS)	bookworm	5.15.0+dfsg1+~cs20.10.9.3-1+deb12u4	vulnerable
	bookworm (security)	5.15.0+dfsg1+~cs20.10.9.3-1+deb12u3	vulnerable
	trixie	7.3.0+dfsg1+~cs24.12.11-1	vulnerable
	forky	7.18.2+dfsg+~cs3.2.0-1	vulnerable
	sid	7.24.6+dfsg+~cs3.2.0-2	fixed

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

Package	Type	Release	Fixed Version	Urgency	Origin	Debian Bugs
node-undici	source	(unstable)	7.24.5+dfsg+~cs3.2.0-1			1130880

Notes

https://github.com/nodejs/undici/security/advisories/GHSA-vrm6-8vpv-qv8q
https://github.com/nodejs/undici/commit/4b4f93ae292f0d245d3957bc08ee2e03d0839faa (v6.24.0)
https://github.com/nodejs/undici/commit/2ee00cb322c76b0bf56829462d7c1dc53d1cbe3d (v7.24.0)