CVE-2026-56406 is an integer overflow or wraparound vulnerability in the libexpat XML parsing library. Specifically, versions prior to 2.8.2 lack a necessary integer overflow check in the XML_ParseBuffer function, which is present in XML_Parse. This can cause incorrect memory handling during XML parsing, potentially leading to data corruption or other impacts on confidentiality and integrity.

The vulnerability can result in high impact on confidentiality and integrity, and low impact on availability, as indicated by the CVSS vector. Exploitation could allow an attacker with local access to cause memory corruption or data manipulation within the affected application using libexpat. No known exploits are reported in the wild.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. No official fix or patch information is provided at this time. Users should monitor libexpat project advisories for updates and apply any forthcoming patches promptly.