RHSA-2026:20558 — Security Advisory

An update for xorg-x11-server is now available for Red Hat Enterprise Linux 9.6 Extended Update Support.

Red Hat Product Security has rated this update as having a security impact of Important. A Common Vulnerability Scoring System (CVSS) base score, which gives a detailed severity rating, is available for each vulnerability from the CVE link(s) in the References section.

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: xwayland: X.Org X server: Denial of Service via integer underflow in XKB compatibility map handling (CVE-2026-33999)

• xwayland: xorg: X.Org X server: Information disclosure and denial of service via out-of-bounds read in XKB geometry processing. (CVE-2026-34000)

• xorg: xwayland: X.Org X server: Use-after-free vulnerability leads to server crash and potential memory corruption (CVE-2026-34001)

• xorg: xwayland: X.Org X server: Information disclosure or Denial of Service via out-of-bounds read in XKB modifier map handling (CVE-2026-34002)

• xorg: xwayland: X.Org X server: Information exposure and denial of service via out-of-bounds memory access (CVE-2026-34003)

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.