CVE-2026-56131

Severity: medium (CVSS 4.9 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-06-19 · updated 2026-10-26
Weakness: CWE-416

Description

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).

Affected products

libexpat project libexpat: before 2.8.2 — fixed in 2.8.2

How to fix

Upgrade to a fixed version: libexpat project libexpat 2.8.2. Check the vendor advisory for mitigations.

References

https://github.com/libexpat/libexpat/pull/1267

Get alerted when CVE-2026-56131 or the next vulnerability affects your stack