RHSA-2026:36085 — 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-x11-server: xorg-x11-server-Xwayland: xorg-x11-server: stack buffer overflow in font alias resolution due to libXfont2 name length mismatch (CVE-2026-50256)

• xorg-x11-server: xorg-x11-server-Xwayland: xorg-x11-server: use-after-free in miSyncDestroyFence() (CVE-2026-50257)

• xorg-x11-server: xorg-x11-server-Xwayland: xorg-x11-server: stack buffer overflow in XKB key types due to unchecked shift levels (CVE-2026-50258)

• xorg-x11-server: xorg-x11-server-Xwayland: xorg-x11-server: stack buffer overflow in XKB SetMap request via mapWidths indexing (CVE-2026-50259)

• xorg-x11-server: xorg-x11-server-Xwayland: xorg-x11-server: use-after-free in FreeCounter() (CVE-2026-50260)

• xorg-x11-server: xorg-x11-server-Xwayland: xorg-x11-server: use-after-free in SyncChangeCounter() (CVE-2026-50261)

• xorg-x11-server: xorg-x11-server-Xwayland: xorg-x11-server: out-of-bounds read/write in GLX ChangeDrawableAttributes (CVE-2026-50262)

• xorg-x11-server: xorg-x11-server-Xwayland: xorg-x11-server: use-after-free information disclosure in CreateSaverWindow() (CVE-2026-50263)

• xorg-x11-server: xorg-x11-server-Xwayland: xorg-x11-server: out-of-bounds heap write in DRI2 DRIGetBuffers/DRIGetBuffersWithFormat (CVE-2026-50264)

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.