CVE-2026-56131 is a use-after-free vulnerability (CWE-416) in the libexpat XML parsing library prior to version 2.8.2. The issue arises because the library does not track the depth of handler calls when XML_ResumeParser is invoked from within handlers in cases of policy violations. This flaw can cause a use-after-free condition similar to CVE-2026-50219, potentially leading to memory corruption. The vulnerability has a CVSS 3.1 base score of 4.9, indicating medium severity, with attack vector local, high attack complexity, no privileges required, no user interaction, and impacts on confidentiality, integrity, and availability at a low level.

Successful exploitation could result in memory corruption due to use-after-free, potentially causing application crashes or limited information disclosure or modification. The impact is rated as medium severity with low-level confidentiality, integrity, and availability impacts. There are no known exploits in the wild at this time.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. No official fix or patch is currently documented. Users should monitor libexpat project advisories for updates addressing this vulnerability. Until a patch is available, avoid invoking XML_ResumeParser from within handlers during policy violations if possible.