Use-after-free in expat - CVE-2026-76957

CSH
CYBERSECURITY HELP
Sign In REGISTER
 
Main Vulnerability Database Vulnerabilities #VU149950

Use-after-free in expat - CVE-2026-76957

Published: September 15, 2026


Vulnerability identifier: #VU149950
CSH Severity: Medium
CVSS v4: 6.9 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-76957
CWE-ID: CWE-416
Exploitation vector: Remote access
Exploit availability: No public exploit available

Vulnerability details

The vulnerability allows a remote attacker to compromise vulnerable system.

The vulnerability exists due to a lack of handler call depth tracking with custom encoding callbacks. A remote attacker can pass specially crafted XML input to the application, trigger a use-after-free error and perform a denial of service attack.


Affected software

expat
openEuler
Fedora
expat-devel
expat-help
expat-debugsource
expat-debuginfo
expat
mingw-expat

How to mitigate CVE-2026-76957

Install updates from vendor's website.

expat - update to 2.8.4
expat-devel - addressed in versions 2.2.9-33, 2.4.1-31, 2.5.0-27, 2.8.1-8
expat-help - addressed in versions 2.2.9-33, 2.4.1-31, 2.5.0-27, 2.8.1-8
expat-debugsource - addressed in versions 2.2.9-33, 2.4.1-31, 2.5.0-27, 2.8.1-8
expat-debuginfo - addressed in versions 2.2.9-33, 2.4.1-31, 2.5.0-27, 2.8.1-8
expat - addressed in versions 2.2.9-33, 2.4.1-31, 2.5.0-27, 2.8.1-8
mingw-expat - addressed in versions 2.8.4-1.fc43, 2.8.4-1.fc44, 2.8.4-1.fc45

External References

Related Security Bulletins