High RHSA-2026:50117 1 CVE

Red Hat Security Advisory: xorg-x11-server security update

Published Aug 5, 2026 · Updated Aug 12, 2026

Ecosystem: Red Hat

Fixed packages 11

Release	Package	Fixed in
Red Hat · RHEL 7 ELS rhel_els:7	xorg-x11-server	0:1.20.4-36.el7_9
Red Hat · RHEL 7 ELS rhel_els:7	xorg-x11-server-common	0:1.20.4-36.el7_9
Red Hat · RHEL 7 ELS rhel_els:7	xorg-x11-server-debuginfo	0:1.20.4-36.el7_9
Red Hat · RHEL 7 ELS rhel_els:7	xorg-x11-server-devel	0:1.20.4-36.el7_9
Red Hat · RHEL 7 ELS rhel_els:7	xorg-x11-server-source	0:1.20.4-36.el7_9
Red Hat · RHEL 7 ELS rhel_els:7	xorg-x11-server-Xdmx	0:1.20.4-36.el7_9
Red Hat · RHEL 7 ELS rhel_els:7	xorg-x11-server-Xephyr	0:1.20.4-36.el7_9
Red Hat · RHEL 7 ELS rhel_els:7	xorg-x11-server-Xnest	0:1.20.4-36.el7_9
Red Hat · RHEL 7 ELS rhel_els:7	xorg-x11-server-Xorg	0:1.20.4-36.el7_9
Red Hat · RHEL 7 ELS rhel_els:7	xorg-x11-server-Xvfb	0:1.20.4-36.el7_9
Red Hat · RHEL 7 ELS rhel_els:7	xorg-x11-server-Xwayland	0:1.20.4-36.el7_9

Vulnerabilities 1

High 8.5

CVE-2026-55999

xorg-server / xwayland glamor font atlas Heap Buffer Overflow

Local attackers with a X connection able to provide PCX fonts to the X server xorg-server before 21.2.24 and xwayland before 24.1.13 could cause a heap buffer overflow via SetFont due to missing glyph boundary checks.

X.Org xwayland xorg-server xorg-server Debian Ubuntu Azure Linux Alpine Wolfi

Jul 8, 2026

References

article
https://access.redhat.com/security/updates/classification/#important
report
https://bugzilla.redhat.com/show_bug.cgi?id=2496165
advisory
https://security.access.redhat.com/data/csaf/v2/advisories/2026/rhsa-2026_50117.json
report
https://access.redhat.com/security/cve/CVE-2026-55999
advisory
https://www.cve.org/CVERecord?id=CVE-2026-55999
advisory
https://nvd.nist.gov/vuln/detail/CVE-2026-55999