RHSA-2026:49516: Important: xorg-x11-server security update

Published Aug 3, 2026
·
Updated

X.Org is an open-source implementation of the X Window System. It provides the basic low-level functionality that full-fledged graphical user interfaces are designed upon.Security Fix(es): xorg: X11: xserver: X.org: glamor Font Atlas Heap Buffer Overflow (CVE-2026-55999) For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

Affected Software

13 affected componentsFixes available
redhat/xorg-x11-server<1.20.11-29.el9_4.1
1.20.11-29.el9_4.1
redhat/xorg-x11-server-common<1.20.11-29.el9_4.1
1.20.11-29.el9_4.1
redhat/xorg-x11-server-debuginfo<1.20.11-29.el9_4.1
1.20.11-29.el9_4.1
redhat/xorg-x11-server-debugsource<1.20.11-29.el9_4.1
1.20.11-29.el9_4.1
redhat/xorg-x11-server-common<1.20.11-29.el9_4.1
1.20.11-29.el9_4.1
redhat/xorg-x11-server-debuginfo<1.20.11-29.el9_4.1
1.20.11-29.el9_4.1
redhat/xorg-x11-server-debugsource<1.20.11-29.el9_4.1
1.20.11-29.el9_4.1
redhat/xorg-x11-server-common<1.20.11-29.el9_4.1.aa
1.20.11-29.el9_4.1.aa
redhat/xorg-x11-server-debuginfo<1.20.11-29.el9_4.1.aa
1.20.11-29.el9_4.1.aa
redhat/xorg-x11-server-debugsource<1.20.11-29.el9_4.1.aa
1.20.11-29.el9_4.1.aa
redhat/xorg-x11-server-common<1.20.11-29.el9_4.1
1.20.11-29.el9_4.1
redhat/xorg-x11-server-debuginfo<1.20.11-29.el9_4.1
1.20.11-29.el9_4.1
redhat/xorg-x11-server-debugsource<1.20.11-29.el9_4.1
1.20.11-29.el9_4.1

Remediation

Recommended actions to resolve this vulnerability, in priority order.

  1. Upgrade

    Upgrade redhat/xorg-x11-server to a version that resolves this vulnerability.

    Fixed in 1.20.11-29.el9_4.1
  2. Upgrade

    Upgrade redhat/xorg-x11-server-common to a version that resolves this vulnerability.

    Fixed in 1.20.11-29.el9_4.1
  3. Upgrade

    Upgrade redhat/xorg-x11-server-debuginfo to a version that resolves this vulnerability.

    Fixed in 1.20.11-29.el9_4.1
  4. Upgrade

    Upgrade redhat/xorg-x11-server-debugsource to a version that resolves this vulnerability.

    Fixed in 1.20.11-29.el9_4.1
  5. Upgrade

    Upgrade redhat/xorg-x11-server-common to a version that resolves this vulnerability.

    Fixed in 1.20.11-29.el9_4.1.aa
  6. Upgrade

    Upgrade redhat/xorg-x11-server-debuginfo to a version that resolves this vulnerability.

    Fixed in 1.20.11-29.el9_4.1.aa
  7. Upgrade

    Upgrade redhat/xorg-x11-server-debugsource to a version that resolves this vulnerability.

    Fixed in 1.20.11-29.el9_4.1.aa
  8. Compensating control

    Apply the security update for xorg-x11-server (X.Org X11 xserver) that fixes the glamor Font Atlas Heap Buffer Overflow (CVE-2026-55999). Use Red Hat article https://access.redhat.com/articles/11258 for application details.

Event History

Aug 3, 2026
Advisory Published
via Red Hat·12:00 AM
Data Sourced
via Red Hat·12:00 AM
RemedyDescriptionAffected Software
Free Weekly Intel

Don't miss critical vulnerabilities

Join thousands of security professionals who receive our weekly digest of trending CVEs, zero-days, and exploited vulnerabilities.

No spam. Unsubscribe anytime.

Company

Resources

Contact

SecAlerts Pty Ltd.
132 Wickham Terrace
Fortitude Valley,
QLD 4006, Australia
info@secalerts.co
By using SecAlerts services, you agree to our services end-user license agreement. This website is safeguarded by reCAPTCHA and governed by the Google Privacy Policy and Terms of Service. All names, logos, and brands of products are owned by their respective owners, and any usage of these names, logos, and brands for identification purposes only does not imply endorsement. If you possess any content that requires removal, please get in touch with us.
© 2026 SecAlerts Pty Ltd.
ABN: 70 645 966 203, ACN: 645 966 203