RHSA-2026:91365HighCVSS 7.5

Red Hat Security Advisory: libX11 security update

Published
October 29, 2026
Last Modified
October 30, 2026

🔗 CVE IDs covered (1)

CVE-2026-88806 →

📋 Description

CVE-2026-88806 — libX11: libX11: Heap-based buffer overflow via malicious X server

🎯 Affected products33

  • Red Hat Enterprise Linux AppStream (v. 9)
  • libX11-0:1.8.12-1.el9_8.1.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 9)
  • libX11-0:1.8.12-1.el9_8.1.i686 as a component of Red Hat Enterprise Linux AppStream (v. 9)
  • libX11-0:1.8.12-1.el9_8.1.ppc64le as a component of Red Hat Enterprise Linux AppStream (v. 9)
  • libX11-0:1.8.12-1.el9_8.1.s390x as a component of Red Hat Enterprise Linux AppStream (v. 9)
  • libX11-0:1.8.12-1.el9_8.1.src as a component of Red Hat Enterprise Linux AppStream (v. 9)
  • libX11-0:1.8.12-1.el9_8.1.x86_64 as a component of Red Hat Enterprise Linux AppStream (v. 9)
  • libX11-common-0:1.8.12-1.el9_8.1.noarch as a component of Red Hat Enterprise Linux AppStream (v. 9)
  • libX11-debuginfo-0:1.8.12-1.el9_8.1.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 9)
  • libX11-debuginfo-0:1.8.12-1.el9_8.1.i686 as a component of Red Hat Enterprise Linux AppStream (v. 9)
  • libX11-debuginfo-0:1.8.12-1.el9_8.1.ppc64le as a component of Red Hat Enterprise Linux AppStream (v. 9)
  • libX11-debuginfo-0:1.8.12-1.el9_8.1.s390x as a component of Red Hat Enterprise Linux AppStream (v. 9)
  • libX11-debuginfo-0:1.8.12-1.el9_8.1.x86_64 as a component of Red Hat Enterprise Linux AppStream (v. 9)
  • libX11-debugsource-0:1.8.12-1.el9_8.1.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 9)
  • libX11-debugsource-0:1.8.12-1.el9_8.1.i686 as a component of Red Hat Enterprise Linux AppStream (v. 9)
  • libX11-debugsource-0:1.8.12-1.el9_8.1.ppc64le as a component of Red Hat Enterprise Linux AppStream (v. 9)
  • libX11-debugsource-0:1.8.12-1.el9_8.1.s390x as a component of Red Hat Enterprise Linux AppStream (v. 9)
  • libX11-debugsource-0:1.8.12-1.el9_8.1.x86_64 as a component of Red Hat Enterprise Linux AppStream (v. 9)
  • libX11-devel-0:1.8.12-1.el9_8.1.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 9)
  • libX11-devel-0:1.8.12-1.el9_8.1.i686 as a component of Red Hat Enterprise Linux AppStream (v. 9)
  • libX11-devel-0:1.8.12-1.el9_8.1.ppc64le as a component of Red Hat Enterprise Linux AppStream (v. 9)
  • libX11-devel-0:1.8.12-1.el9_8.1.s390x as a component of Red Hat Enterprise Linux AppStream (v. 9)
  • libX11-devel-0:1.8.12-1.el9_8.1.x86_64 as a component of Red Hat Enterprise Linux AppStream (v. 9)
  • libX11-xcb-0:1.8.12-1.el9_8.1.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 9)
  • libX11-xcb-0:1.8.12-1.el9_8.1.i686 as a component of Red Hat Enterprise Linux AppStream (v. 9)
  • libX11-xcb-0:1.8.12-1.el9_8.1.ppc64le as a component of Red Hat Enterprise Linux AppStream (v. 9)
  • libX11-xcb-0:1.8.12-1.el9_8.1.s390x as a component of Red Hat Enterprise Linux AppStream (v. 9)
  • libX11-xcb-0:1.8.12-1.el9_8.1.x86_64 as a component of Red Hat Enterprise Linux AppStream (v. 9)
  • libX11-xcb-debuginfo-0:1.8.12-1.el9_8.1.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 9)
  • libX11-xcb-debuginfo-0:1.8.12-1.el9_8.1.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 this issue, users should avoid connecting to untrusted X servers. When using SSH, ensure that X11 forwarding (`ssh -X` or `ssh -Y`) is only enabled for trusted remote hosts. To prevent X11 forwarding for specific hosts, add `ForwardX11 no` to the relevant host entry in `~/.ssh/config` or `/etc/ssh/ssh_config`. Alternatively, disable X11 forwarding globally by setting `ForwardX11 no` in `/etc/ssh/ssh_config`.

🔗 References (4)