CVE-2026-56411 is an integer overflow or wraparound vulnerability (CWE-190) in the libexpat project's xmlwf tool, specifically in the endDoctypeDecl function when handling NOTATION declarations. This vulnerability affects all libexpat versions prior to 2.8.2. The integer overflow could potentially be exploited to cause memory corruption or other unintended behavior, impacting confidentiality and integrity of the system. No official patch or remediation level has been documented yet, and no known exploits are reported in the wild.

The vulnerability can lead to a high impact on confidentiality and integrity, meaning an attacker might be able to manipulate or access sensitive data. The availability impact is low, indicating the vulnerability is less likely to cause denial of service. The attack vector is local with high attack complexity, and no privileges or user interaction are required, according to the CVSS vector.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Since no official fix or patch is documented, users should monitor libexpat project advisories for updates. Until a patch is available, avoid processing untrusted NOTATION declarations with xmlwf or limit usage to trusted inputs.