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
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Frequently Asked Questions

1

What is the severity of RHSA-2026:49516?

The severity of RHSA-2026:49516 is classified as Important.

2

What vulnerability is addressed in RHSA-2026:49516?

RHSA-2026:49516 addresses a buffer overflow vulnerability identified as CVE-2026-55999 in the X.Org server.

3

How do I fix RHSA-2026:49516?

To fix RHSA-2026:49516, you should update the xorg-x11-server packages to the latest version available from your Red Hat repository.

4

What software is affected by RHSA-2026:49516?

The affected software for RHSA-2026:49516 includes the xorg-x11-server-common, xorg-x11-server-debuginfo, and xorg-x11-server packages.

5

What is the risk associated with the vulnerability in RHSA-2026:49516?

The risk associated with the buffer overflow vulnerability in RHSA-2026:49516 could potentially allow an attacker to execute arbitrary code.

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