What is CVE-2026-56131?

CVE-2026-56131 is a medium-severity vulnerability in Libexpat Project, classified under Use After Free. CVSS score: 4.9/10. Published 2026-06-19.

How severe is CVE-2026-56131?

Medium severity. CVSS v3 base score is 4.9 out of 10.

Use After Free in Libexpat Project

CVE-2026-56131

libexpat before 2.8.2 lacks handler call depth tracking for calls to XML_ResumeParser from within handlers in cases of a policy violation. Thus, a use-after-free can occur (similar to the CVE-2026-50219 situation).

Vulnerability class: Use-After-Free

EPSS: 0.001 (3.4th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 4.9 (Medium). Vector: CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L.

Affected products

Libexpat Project — versions 0
Libexpat_project Libexpat

Weakness classification (CWE)

CWE-416 — Use After Free

References

cve@mitre.org (Patch)

Frequently asked questions

What is CVE-2026-56131?: CVE-2026-56131 is a medium-severity vulnerability in Libexpat Project, classified under Use After Free. CVSS score: 4.9/10. Published 2026-06-19.
How severe is CVE-2026-56131?: Medium severity. CVSS v3 base score is 4.9 out of 10.