RHSA-2026:72663HighCVSS 7.5

Red Hat Security Advisory: expat security update

Published
September 29, 2026
Last Modified
September 29, 2026

🔗 CVE IDs covered (2)

CVE-2026-66046 →CVE-2026-93990 →

📋 Description

CVE-2026-66046 — expat: Expat: Denial of Service via quadratic complexity in attribute processing CVE-2026-93990 — expat: Expat: XML Injection via Malformed UTF-16 Input

🎯 Affected products33

  • Red Hat Enterprise Linux AppStream (v. 9)
  • Red Hat Enterprise Linux BaseOS (v. 9)
  • expat-0:2.5.0-6.el9_8.5.aarch64 as a component of Red Hat Enterprise Linux BaseOS (v. 9)
  • expat-0:2.5.0-6.el9_8.5.i686 as a component of Red Hat Enterprise Linux BaseOS (v. 9)
  • expat-0:2.5.0-6.el9_8.5.ppc64le as a component of Red Hat Enterprise Linux BaseOS (v. 9)
  • expat-0:2.5.0-6.el9_8.5.s390x as a component of Red Hat Enterprise Linux BaseOS (v. 9)
  • expat-0:2.5.0-6.el9_8.5.src as a component of Red Hat Enterprise Linux BaseOS (v. 9)
  • expat-0:2.5.0-6.el9_8.5.x86_64 as a component of Red Hat Enterprise Linux BaseOS (v. 9)
  • expat-debuginfo-0:2.5.0-6.el9_8.5.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 9)
  • expat-debuginfo-0:2.5.0-6.el9_8.5.aarch64 as a component of Red Hat Enterprise Linux BaseOS (v. 9)
  • expat-debuginfo-0:2.5.0-6.el9_8.5.i686 as a component of Red Hat Enterprise Linux AppStream (v. 9)
  • expat-debuginfo-0:2.5.0-6.el9_8.5.i686 as a component of Red Hat Enterprise Linux BaseOS (v. 9)
  • expat-debuginfo-0:2.5.0-6.el9_8.5.ppc64le as a component of Red Hat Enterprise Linux AppStream (v. 9)
  • expat-debuginfo-0:2.5.0-6.el9_8.5.ppc64le as a component of Red Hat Enterprise Linux BaseOS (v. 9)
  • expat-debuginfo-0:2.5.0-6.el9_8.5.s390x as a component of Red Hat Enterprise Linux AppStream (v. 9)
  • expat-debuginfo-0:2.5.0-6.el9_8.5.s390x as a component of Red Hat Enterprise Linux BaseOS (v. 9)
  • expat-debuginfo-0:2.5.0-6.el9_8.5.x86_64 as a component of Red Hat Enterprise Linux AppStream (v. 9)
  • expat-debuginfo-0:2.5.0-6.el9_8.5.x86_64 as a component of Red Hat Enterprise Linux BaseOS (v. 9)
  • expat-debugsource-0:2.5.0-6.el9_8.5.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 9)
  • expat-debugsource-0:2.5.0-6.el9_8.5.aarch64 as a component of Red Hat Enterprise Linux BaseOS (v. 9)
  • expat-debugsource-0:2.5.0-6.el9_8.5.i686 as a component of Red Hat Enterprise Linux AppStream (v. 9)
  • expat-debugsource-0:2.5.0-6.el9_8.5.i686 as a component of Red Hat Enterprise Linux BaseOS (v. 9)
  • expat-debugsource-0:2.5.0-6.el9_8.5.ppc64le as a component of Red Hat Enterprise Linux AppStream (v. 9)
  • expat-debugsource-0:2.5.0-6.el9_8.5.ppc64le as a component of Red Hat Enterprise Linux BaseOS (v. 9)
  • expat-debugsource-0:2.5.0-6.el9_8.5.s390x as a component of Red Hat Enterprise Linux AppStream (v. 9)
  • expat-debugsource-0:2.5.0-6.el9_8.5.s390x as a component of Red Hat Enterprise Linux BaseOS (v. 9)
  • expat-debugsource-0:2.5.0-6.el9_8.5.x86_64 as a component of Red Hat Enterprise Linux AppStream (v. 9)
  • expat-debugsource-0:2.5.0-6.el9_8.5.x86_64 as a component of Red Hat Enterprise Linux BaseOS (v. 9)
  • expat-devel-0:2.5.0-6.el9_8.5.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 9)
  • expat-devel-0:2.5.0-6.el9_8.5.i686 as a component of Red Hat Enterprise Linux AppStream (v. 9)
  • +3 more not shown

✅ Remediation

For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258 Workaround: To mitigate, avoid parsing untrusted XML where possible. Where parsing is required, restrict sources using network controls and enforce strict limits on document size, attribute counts, and request rates at the application or proxy level. Additionally, apply strict execution timeouts to cap parser cost and interrupt processes before they can exhaust CPU resources. Workaround: To mitigate this restrict which hosts can send XML (including UTF-16) to Expat-based services with a host firewall and network segmentation. Where applications allow, prefer UTF-8-only input and reject unexpected encodings.

🔗 References (5)