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
NISTPrimary
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: 1.04%
Affected Products (NVD)
VendorProductVersion
libexpat_projectlibexpat
𝑥
< 2.8.4
𝑥
= Vulnerable software versions
Debian logo
Debian Releases
Debian Product
Codename
expat
bookworm
vulnerable
bookworm (security)
2.5.0-1+deb12u3
fixed
forky
2.8.4-2
fixed
sid
2.8.5-1
fixed
trixie
no-dsa
trixie (security)
vulnerable
Ubuntu logo
Ubuntu Releases
Ubuntu Product
Codename
expat
bionic
Fixed 2.2.5-3ubuntu0.9+esm5
released
focal
Fixed 2.2.9-1ubuntu0.8+esm3
released
jammy
Fixed 2.4.7-1ubuntu0.9
released
noble
Fixed 2.6.1-2ubuntu0.6
released
resolute
Fixed 2.7.4-1ubuntu0.2
released
trusty
Fixed 2.1.0-4ubuntu1.4+esm13
released
xenial
Fixed 2.1.0-7ubuntu0.16.04.5+esm14
released
apache2
bionic
not-affected
focal
not-affected
jammy
not-affected
noble
not-affected
resolute
not-affected
trusty
not-affected
xenial
not-affected
apr-util
bionic
not-affected
focal
not-affected
jammy
not-affected
noble
not-affected
resolute
not-affected
trusty
not-affected
xenial
not-affected
cmake
bionic
not-affected
focal
not-affected
jammy
not-affected
noble
not-affected
resolute
not-affected
xenial
not-affected
ghostscript
bionic
not-affected
focal
not-affected
jammy
not-affected
noble
not-affected
resolute
not-affected
xenial
not-affected
texlive-bin
bionic
not-affected
focal
not-affected
jammy
not-affected
noble
not-affected
resolute
not-affected
xenial
not-affected
xmlrpc-c
bionic
needs-triage
focal
needs-triage
jammy
needs-triage
noble
needs-triage
resolute
needs-triage
trusty
needs-triage
xenial
needs-triage
vnc4
bionic
needs-triage
jammy
dne
noble
dne
resolute
dne
trusty
needs-triage
xenial
needs-triage
wbxml2
bionic
needs-triage
focal
needs-triage
jammy
needs-triage
noble
needs-triage
resolute
needs-triage
xenial
needs-triage
swish-e
bionic
needs-triage
focal
needs-triage
jammy
needs-triage
noble
needs-triage
resolute
needs-triage
xenial
needs-triage
insighttoolkit4
bionic
needs-triage
focal
needs-triage
jammy
needs-triage
noble
dne
resolute
dne
xenial
needs-triage
cadaver
bionic
needs-triage
focal
needs-triage
jammy
needs-triage
noble
needs-triage
resolute
needs-triage
xenial
needs-triage
gdcm
bionic
needs-triage
focal
not-affected
jammy
not-affected
noble
not-affected
resolute
not-affected
trusty
not-affected
xenial
needs-triage
ayttm
jammy
dne
noble
dne
resolute
dne
xenial
needs-triage
cableswig
jammy
dne
noble
dne
resolute
dne
xenial
needs-triage
coin3
bionic
needs-triage
focal
not-affected
jammy
not-affected
noble
not-affected
resolute
not-affected
trusty
needs-triage
xenial
needs-triage
matanza
bionic
needs-triage
focal
ignored
jammy
ignored
noble
ignored
resolute
ignored
xenial
needs-triage
tdom
bionic
needs-triage
focal
needs-triage
jammy
needs-triage
noble
needs-triage
resolute
needs-triage
xenial
needs-triage
vtk
jammy
dne
noble
dne
resolute
dne
trusty
needs-triage
xenial
needs-triage
smart
bionic
needs-triage
jammy
dne
noble
dne
resolute
dne
xenial
needs-triage
firefox
jammy
not-affected
noble
not-affected
resolute
not-affected
thunderbird
jammy
not-affected
noble
not-affected
resolute
not-affected
libxmltok
bionic
needs-triage
focal
needs-triage
jammy
needs-triage
noble
needs-triage
resolute
dne
xenial
needs-triage
Amazon Linux logo
Amazon Linux Releases
Amazon Package
Release
expat
Amazon Linux 2023
0:2.8.3-1.amzn2023.0.1
fixed
expat-debuginfo
Amazon Linux 2023
0:2.8.3-1.amzn2023.0.1
fixed
expat-debugsource
Amazon Linux 2023
0:2.8.3-1.amzn2023.0.1
fixed
expat-devel
Amazon Linux 2023
0:2.8.3-1.amzn2023.0.1
fixed
expat-static
Amazon Linux 2023
0:2.8.3-1.amzn2023.0.1
fixed
firefox
Amazon Linux 2023
0:140.14.0-1.amzn2023.0.1
fixed
firefox-debuginfo
Amazon Linux 2023
0:140.14.0-1.amzn2023.0.1
fixed
firefox-debugsource
Amazon Linux 2023
0:140.14.0-1.amzn2023.0.1
fixed
thunderbird
Amazon Linux 2
0:140.14.0-1.amzn2.0.1
fixed
Azure Linux logo
Azure Linux Releases
Azure Package
Release
expat
Azure Linux 3.0
0:2.8.3-2.azl3
fixed
Common Weakness Enumeration
References
https://github.com/libexpat/libexpat/pull/1322
https://github.com/libexpat/libexpat/pull/1329