CVE-2026-66299

NameCVE-2026-66299
DescriptionUncontrolled Resource Consumption vulnerability in Apache Tomcat's WebSocket chat example. This issue affects Apache Tomcat: from 11.0.0-M20 through 11.0.24, from 10.1.24 through 10.1.57, from 9.0.89 through 9.0.120. Users who have followed the security guidance to remove the examples web application are not affected by this issue. Users are recommended to remove the examples web application or to upgrade to version 11.0.25, 10.1.58 or 9.0.121 (when released), which fix the issue.
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
tomcat10 (PTS)bookworm, bookworm (security)10.1.55-1~deb12u1vulnerable
trixie (security), trixie10.1.55-1~deb13u1vulnerable
forky, sid10.1.55-1vulnerable
tomcat11 (PTS)trixie (security), trixie11.0.22-1~deb13u1vulnerable
forky, sid11.0.24-1vulnerable
tomcat9 (PTS)bullseye9.0.43-2~deb11u10vulnerable
bullseye (security)9.0.118-0+deb11u1fixed
bookworm9.0.70-2fixed
trixie9.0.95-1fixed
forky, sid9.0.118-1fixed

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

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
tomcat10source(unstable)(unfixed)unimportant
tomcat11source(unstable)(unfixed)unimportant
tomcat9source(unstable)9.0.70-2unimportant

Notes

Starting with 9.0.70-2 src:tomcat9 no longer ships the server stack, using that as the fixed version
https://lists.apache.org/thread/8owczcc1o8qw1rxmg9gvfk4w2jnh4l5k
Only affects the WebSocket chat example

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