CVE-2026-76957

NameCVE-2026-76957
Descriptionlibexpat before 2.8.4 lacks handler call depth tracking with custom encoding callbacks. Thus, a use-after-free can occur. NOTE: this is similar to CVE-2026-50219, CVE-2026-56131 and CVE-2026-56412.
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)
ReferencesDLA-4765-1
Debian Bugs1144927

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
expat (PTS)bookworm2.5.0-1+deb12u2vulnerable
bookworm (security)2.5.0-1+deb12u3fixed
trixie2.7.1-2vulnerable
trixie (security)2.8.3-1~deb13u1vulnerable
sid, forky2.8.4-1fixed

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

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
expatsourcebookworm2.5.0-1+deb12u3DLA-4765-1
expatsource(unstable)2.8.4-11144927

Notes

[trixie] - expat <no-dsa> (Minor issue)
https://github.com/libexpat/libexpat/pull/1322
Fixed by: https://github.com/libexpat/libexpat/commit/127b7d4beb8fe7e5ce5cb021c2e56379c95863d0 (R_2_8_4)
Fixed by: https://github.com/libexpat/libexpat/commit/acbd2e1179c04fe9a8c3f3837701904d05de71fc (R_2_8_4)

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