CVE-2026-76957

EUVD-2026-63196
libexpat 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.
ProviderTypeBase ScoreAtk. VectorAtk. ComplexityPriv. RequiredVector
mitreCNA
4.9 MEDIUM
LOCAL
HIGH
NONE
CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L
Base Score
CVSS 3.x
EPSS Score
Percentile: 1.1%
Early Detection
Affected products identified ahead of NVD analysis through intelligence sources.
VendorProductVersionSource
libexpat_projectlibexpat
𝑥
< 2.8.4
CNA
Debian logo
Debian Releases
Debian Product
Codename
expat
bookworm
vulnerable
bookworm (security)
vulnerable
bullseye
vulnerable
bullseye (security)
vulnerable
forky
vulnerable
sid
vulnerable
trixie
vulnerable
trixie (security)
vulnerable
Common Weakness Enumeration
Vulnerability Media Exposure
References
https://github.com/libexpat/libexpat/pull/1322
https://github.com/libexpat/libexpat/pull/1329