CVE-2026-15565

NameCVE-2026-15565
DescriptionA flaw was found in Undertow. A remote attacker can cause Out of Memory on websockets endpoint without authentication on any @ServerEndpoint class that has any @OnMessage method. This allows an attacker to cause Denial of Service attack without authentication and using only a standard WebSocket handshake.
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
undertow (PTS)forky, sid2.3.20-1vulnerable

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

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
undertowsource(unstable)(unfixed)

Notes

https://bugzilla.redhat.com/show_bug.cgi?id=2490628

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