CVE-2026-45186 is a vulnerability in the libexpat XML parsing library prior to version 2.8.1, where the computational complexity of attribute name collision checks is inefficient. This inefficiency can be exploited by an attacker to cause a denial of service via moderately sized crafted XML input. The vulnerability is classified under CWE-407 (Inefficient Algorithmic Complexity). Red Hat has published multiple advisories and errata providing security updates for affected Red Hat Enterprise Linux 10 variants, mitigating this issue.

The vulnerability allows denial of service (DoS) attacks by causing excessive computational resource consumption during XML parsing. There is no impact on confidentiality or integrity. The CVSS v3.1 base score is 2.9 (low severity), reflecting the limited impact and the requirement for local access with high attack complexity.

Red Hat has released security updates for Red Hat Enterprise Linux 10 that address this vulnerability. Users should apply the provided updates as detailed in the Red Hat advisories (e.g., RHSA-2026:22715) to remediate the issue. Patch status is confirmed by the vendor advisories. No additional mitigation is required beyond applying the official fixes.