Red Hat Security Advisory: Red Hat Hardened Images RPMs Security Update

The vulnerability identified as CVE-2026-76956 affects libexpat versions 2.8.2 and 2.8.3 prior to 2.8.4. It arises from incorrect handling of the getentropy system call's return code, resulting in insufficient entropy generation. This entropy deficiency makes the library vulnerable to hash flooding attacks, which can be exploited to cause denial of service by processing specially crafted XML content. The issue is present in Red Hat Hardened Images RPMs, specifically expat version 2.8.3-0.1.1.hum1 for aarch64 and x86_64 architectures. Red Hat has released an advisory (RHSA-2026:60451) describing the issue and the affected packages but has not yet provided a fixed package for these hardened images.

The vulnerability can be exploited to cause denial of service through hash flooding attacks due to insufficient entropy in the affected libexpat versions. This impacts systems using the vulnerable Red Hat Hardened Images RPMs with expat 2.8.3-0.1.1.hum1, potentially disrupting XML processing services.

Red Hat has issued a security advisory detailing the vulnerability and affected packages. However, no fixed version is currently available for the Red Hat Hardened Images RPMs. Users should monitor Red Hat's official channels for updates and apply patches once they are released. Until then, consider mitigating exposure by limiting access to services processing untrusted XML content or applying other environment-specific controls.