CVE-2026-76957

Public on 2026-08-20

Modified on 2026-08-24

Description

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.

Severity

Medium

See what this means

CVSS v3 Base Score

4.9

See breakdown

Affected Packages

Platform	Package	Status
Amazon Linux 2 - Core	expat	Pending Fix
Amazon Linux 2023	expat	Pending Fix
Amazon Linux 2 - Firefox Extra	firefox	Pending Fix
Amazon Linux 2023	firefox	Pending Fix
Amazon Linux 2 - Core	thunderbird	Pending Fix
Amazon Linux 2023	xmlrpc-c	Not Affected

CVSS Scores

	Score Type	Score	Vector
Amazon Linux	CVSSv3	4.9	CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L

References

FAQs regarding Amazon Linux ALAS/CVE Severity Red Hat: CVE-2026-76957 Mitre: CVE-2026-76957