CVE-2026-19204

Name	CVE-2026-19204
Description	A client may send a WebSocket frame with an unknown opcode and a very large declared payload length, causing Jetty to attempt a large memory allocation and potentially exhaust the JVM heap. This occurs when auto-fragmentation is enabled, as unknown opcodes bypass the normal maximum frame size handling and payload allocation occurs before the opcode is validated.
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)

Vulnerable and fixed packages

The table below lists information on source packages.

Source Package	Release	Version	Status
jetty12 (PTS)	trixie (security), trixie	12.0.17-3.1~deb13u1	vulnerable
	forky	12.0.33-1	vulnerable
	sid	12.0.40-1	fixed
jetty9 (PTS)	bookworm, bookworm (security)	9.4.57-1.1~deb12u1	fixed
	trixie (security), trixie	9.4.57-1.1~deb13u1	fixed
	forky, sid	9.4.58-2	fixed

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

Package	Type	Release	Fixed Version	Urgency	Origin	Debian Bugs
jetty12	source	(unstable)	12.0.39-1
jetty9	source	(unstable)	(not affected)

- jetty9 <not-affected> (Only affects 10.x and later)
https://github.com/jetty/jetty.project/security/advisories/GHSA-85fq-fc5f-7j7g