CVE-2026-55999
xorg-x11-server-Xwayland: Local attackers with a X connection able to provide PCX fonts to the X server xorg-server before 21.2.24 and xwaylan...
CVE-2026-55999 is fixed in 21 products on 1 platform, first by SUSE-SU-2026:2786-1, released July 8, 2026. It is not reported as exploited. Patch Radar priority: High.
High
CVSS
7.8
important
Exploitation
None reported
No vendor assessment
CISA KEV
Not listed
Not in the Known Exploited Vulnerabilities catalog
EPSS
0.0033
26th percentile
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.
Where it's fixed
| Product | Fixed in | Fix | Released |
|---|---|---|---|
| Linux | |||
| xorg-server · Debian 13.5 (trixie) | 2:21.1.16-1.3+deb13u4 | DEBIAN-CVE-2026-55999 | Jul 8, 2026 |
| xorg-server · Debian 14 | 2:21.1.24-1 | DEBIAN-CVE-2026-55999 | Jul 8, 2026 |
| xorg-x11-server · opensuse-leap 16.0 | 21.1.15-160000.6.1 | OPENSUSE-SU-2026:21273-1 | Jul 8, 2026 |
| xorg-x11-server · rocky 8 | 0:1.20.11-28.el8_10.3 | RLSA-2026:38487 | Jul 14, 2026 |
| xorg-x11-server · rocky 9 | 0:1.20.11-34.el9_8.3 | RLSA-2026:38486 | Jul 14, 2026 |
| xorg-x11-server · sles 15.6 | 21.1.11-150600.5.31.1 | SUSE-SU-2026:2786-1 | Jul 8, 2026 |
| xorg-x11-server · sles 15.7 | 21.1.15-150700.5.22.1 | SUSE-SU-2026:2788-1 | Jul 8, 2026 |
| xorg-x11-server-Xdmx · RHEL 8 | 0:1.20.11-28.el8_10.3 | RHSA-2026:38487 | Jul 13, 2026 |
| xorg-x11-server-Xdmx · RHEL 9 | 0:1.20.11-34.el9_8.3 | RHSA-2026:38486 | Jul 13, 2026 |
| xorg-x11-server-Xdmx · almalinux 8 | 1.20.11-28.el8_10.3 | ALSA-2026:38487 | Jul 13, 2026 |
| xorg-x11-server-Xdmx · almalinux 9 | 1.20.11-34.el9_8.3 | ALSA-2026:38486 | Jul 13, 2026 |
| xorg-x11-server-Xdmx · ol 8 | 0:1.20.11-28.el8_10.3 | ELSA-2026-38487 | Sep 1, 2026 |
| xorg-x11-server-Xdmx · ol 9 | 0:1.20.11-34.el9_8.3 | ELSA-2026-38486 | Jul 13, 2026 |
| xorg-x11-server-Xephyr · RHEL 8 | 0:1.20.11-28.el8_10.3 | RHSA-2026:38487 | Jul 13, 2026 |
| xorg-x11-server-Xephyr · RHEL 9 | 0:1.20.11-34.el9_8.3 | RHSA-2026:38486 | Jul 13, 2026 |
| xorg-x11-server-Xephyr · almalinux 8 | 1.20.11-28.el8_10.3 | ALSA-2026:38487 | Jul 13, 2026 |
| xorg-x11-server-Xephyr · almalinux 9 | 1.20.11-34.el9_8.3 | ALSA-2026:38486 | Jul 13, 2026 |
| xorg-x11-server-Xephyr · amzn 2023 | 21.1.13-5.amzn2023.0.11 | ALAS2023-2026-1943 | Jul 20, 2026 |
| xorg-x11-server-Xephyr · ol 8 | 0:1.20.11-28.el8_10.3 | ELSA-2026-38487 | Sep 1, 2026 |
| xorg-x11-server-Xephyr · ol 9 | 0:1.20.11-34.el9_8.3 | ELSA-2026-38486 | Jul 13, 2026 |
| xorg-x11-server-Xephyr-debuginfo · amzn 2023 | 21.1.13-5.amzn2023.0.11 | ALAS2023-2026-1943 | Jul 20, 2026 |
| xorg-x11-server-Xnest · RHEL 8 | 0:1.20.11-28.el8_10.3 | RHSA-2026:38487 | Jul 13, 2026 |
| xorg-x11-server-Xnest · RHEL 9 | 0:1.20.11-34.el9_8.3 | RHSA-2026:38486 | Jul 13, 2026 |
| xorg-x11-server-Xnest · almalinux 8 | 1.20.11-28.el8_10.3 | ALSA-2026:38487 | Jul 13, 2026 |
| xorg-x11-server-Xnest · almalinux 9 | 1.20.11-34.el9_8.3 | ALSA-2026:38486 | Jul 13, 2026 |
| xorg-x11-server-Xnest · amzn 2023 | 21.1.13-5.amzn2023.0.11 | ALAS2023-2026-1943 | Jul 20, 2026 |
| xorg-x11-server-Xnest · ol 8 | 0:1.20.11-28.el8_10.3 | ELSA-2026-38487 | Sep 1, 2026 |
| xorg-x11-server-Xnest · ol 9 | 0:1.20.11-34.el9_8.3 | ELSA-2026-38486 | Jul 13, 2026 |
| xorg-x11-server-Xnest-debuginfo · amzn 2023 | 21.1.13-5.amzn2023.0.11 | ALAS2023-2026-1943 | Jul 20, 2026 |
| xorg-x11-server-Xorg · RHEL 8 | 0:1.20.11-28.el8_10.3 | RHSA-2026:38487 | Jul 13, 2026 |
| xorg-x11-server-Xorg · RHEL 9 | 0:1.20.11-34.el9_8.3 | RHSA-2026:38486 | Jul 13, 2026 |
| xorg-x11-server-Xorg · almalinux 8 | 1.20.11-28.el8_10.3 | ALSA-2026:38487 | Jul 13, 2026 |
| xorg-x11-server-Xorg · almalinux 9 | 1.20.11-34.el9_8.3 | ALSA-2026:38486 | Jul 13, 2026 |
| xorg-x11-server-Xorg · amzn 2023 | 21.1.13-5.amzn2023.0.11 | ALAS2023-2026-1943 | Jul 20, 2026 |
| xorg-x11-server-Xorg · ol 8 | 0:1.20.11-28.el8_10.3 | ELSA-2026-38487 | Sep 1, 2026 |
| xorg-x11-server-Xorg · ol 9 | 0:1.20.11-34.el9_8.3 | ELSA-2026-38486 | Jul 13, 2026 |
| xorg-x11-server-Xorg-debuginfo · amzn 2023 | 21.1.13-5.amzn2023.0.11 | ALAS2023-2026-1943 | Jul 20, 2026 |
| xorg-x11-server-Xvfb · RHEL 8 | 0:1.20.11-28.el8_10.3 | RHSA-2026:38487 | Jul 13, 2026 |
| xorg-x11-server-Xvfb · RHEL 9 | 0:1.20.11-34.el9_8.3 | RHSA-2026:38486 | Jul 13, 2026 |
| xorg-x11-server-Xvfb · almalinux 8 | 1.20.11-28.el8_10.3 | ALSA-2026:38487 | Jul 13, 2026 |
| xorg-x11-server-Xvfb · almalinux 9 | 1.20.11-34.el9_8.3 | ALSA-2026:38486 | Jul 13, 2026 |
| xorg-x11-server-Xvfb · amzn 2023 | 21.1.13-5.amzn2023.0.11 | ALAS2023-2026-1943 | Jul 20, 2026 |
| xorg-x11-server-Xvfb · ol 8 | 0:1.20.11-28.el8_10.3 | ELSA-2026-38487 | Sep 1, 2026 |
| xorg-x11-server-Xvfb · ol 9 | 0:1.20.11-34.el9_8.3 | ELSA-2026-38486 | Jul 13, 2026 |
| xorg-x11-server-Xvfb-debuginfo · amzn 2023 | 21.1.13-5.amzn2023.0.11 | ALAS2023-2026-1943 | Jul 20, 2026 |
| xorg-x11-server-Xwayland · RHEL 10 | 24.1.5-6.el10_0.2 | RHSA-2026:50100 | Jul 13, 2026 |
| xorg-x11-server-Xwayland · RHEL 8 | 0:21.1.3-20.el8_10.3 | RHSA-2026:38488 | Jul 13, 2026 |
| xorg-x11-server-Xwayland · RHEL 9 | 0:24.1.9-4.el9_8.3 | RHSA-2026:38490 | Jul 13, 2026 |
| xorg-x11-server-Xwayland · almalinux 10 | 24.1.9-4.el10_2.3 | ALSA-2026:38489 | Jul 13, 2026 |
| xorg-x11-server-Xwayland · almalinux 8 | 21.1.3-20.el8_10.3 | ALSA-2026:38488 | Jul 13, 2026 |
| xorg-x11-server-Xwayland · almalinux 9 | 24.1.9-4.el9_8.3 | ALSA-2026:38490 | Jul 13, 2026 |
| xorg-x11-server-Xwayland · amzn 2023 | 24.1.3-1.amzn2023.0.6 | ALAS2023-2026-1944 | Jul 20, 2026 |
| xorg-x11-server-Xwayland · ol 10 | 0:24.1.9-4.el10_2.3 | ELSA-2026-38489 | Sep 1, 2026 |
| xorg-x11-server-Xwayland · ol 8 | 0:21.1.3-20.el8_10.3 | ELSA-2026-38488 | Jul 13, 2026 |
| xorg-x11-server-Xwayland · ol 9 | 0:24.1.9-4.el9_8.3 | ELSA-2026-38490 | Sep 1, 2026 |
| xorg-x11-server-Xwayland · rocky 10 | 0:24.1.9-4.el10_2.3 | RLSA-2026:38489 | Jul 14, 2026 |
| xorg-x11-server-Xwayland · rocky 8 | 0:21.1.3-20.el8_10.3 | RLSA-2026:38488 | Jul 14, 2026 |
| xorg-x11-server-Xwayland · rocky 9 | 0:24.1.9-4.el9_8.3 | RLSA-2026:38490 | Jul 14, 2026 |
| xorg-x11-server-Xwayland-debuginfo · amzn 2023 | 24.1.3-1.amzn2023.0.6 | ALAS2023-2026-1944 | Jul 20, 2026 |
| xorg-x11-server-Xwayland-debugsource · amzn 2023 | 24.1.3-1.amzn2023.0.6 | ALAS2023-2026-1944 | Jul 20, 2026 |
| xorg-x11-server-Xwayland-devel · RHEL 9 | 0:24.1.9-4.el9_8.3 | RHSA-2026:38490 | Jul 13, 2026 |
| xorg-x11-server-Xwayland-devel · almalinux 10 | 24.1.9-4.el10_2.3 | ALSA-2026:38489 | Jul 13, 2026 |
| xorg-x11-server-Xwayland-devel · almalinux 9 | 24.1.9-4.el9_8.3 | ALSA-2026:38490 | Jul 13, 2026 |
| xorg-x11-server-Xwayland-devel · amzn 2023 | 24.1.3-1.amzn2023.0.6 | ALAS2023-2026-1944 | Jul 20, 2026 |
| xorg-x11-server-Xwayland-devel · ol 10 | 0:24.1.9-4.el10_2.3 | ELSA-2026-38489 | Sep 1, 2026 |
| xorg-x11-server-Xwayland-devel · ol 9 | 0:24.1.9-4.el9_8.3 | ELSA-2026-38490 | Sep 1, 2026 |
| xorg-x11-server-common · RHEL 8 | 0:1.20.11-28.el8_10.3 | RHSA-2026:38487 | Jul 13, 2026 |
| xorg-x11-server-common · RHEL 9 | 0:1.20.11-34.el9_8.3 | RHSA-2026:38486 | Jul 13, 2026 |
| xorg-x11-server-common · almalinux 8 | 1.20.11-28.el8_10.3 | ALSA-2026:38487 | Jul 13, 2026 |
| xorg-x11-server-common · almalinux 9 | 1.20.11-34.el9_8.3 | ALSA-2026:38486 | Jul 13, 2026 |
| xorg-x11-server-common · amzn 2023 | 21.1.13-5.amzn2023.0.11 | ALAS2023-2026-1943 | Jul 20, 2026 |
| xorg-x11-server-common · ol 8 | 0:1.20.11-28.el8_10.3 | ELSA-2026-38487 | Sep 1, 2026 |
| xorg-x11-server-common · ol 9 | 0:1.20.11-34.el9_8.3 | ELSA-2026-38486 | Jul 13, 2026 |
| xorg-x11-server-debuginfo · amzn 2023 | 21.1.13-5.amzn2023.0.11 | ALAS2023-2026-1943 | Jul 20, 2026 |
| xorg-x11-server-debugsource · amzn 2023 | 21.1.13-5.amzn2023.0.11 | ALAS2023-2026-1943 | Jul 20, 2026 |
| xorg-x11-server-devel · RHEL 8 | 0:1.20.11-28.el8_10.3 | RHSA-2026:38487 | Jul 13, 2026 |
| xorg-x11-server-devel · RHEL 9 | 0:1.20.11-34.el9_8.3 | RHSA-2026:38486 | Jul 13, 2026 |
| xorg-x11-server-devel · almalinux 8 | 1.20.11-28.el8_10.3 | ALSA-2026:38487 | Jul 13, 2026 |
| xorg-x11-server-devel · almalinux 9 | 1.20.11-34.el9_8.3 | ALSA-2026:38486 | Jul 13, 2026 |
| xorg-x11-server-devel · amzn 2023 | 21.1.13-5.amzn2023.0.11 | ALAS2023-2026-1943 | Jul 20, 2026 |
| xorg-x11-server-devel · ol 8 | 0:1.20.11-28.el8_10.3 | ELSA-2026-38487 | Sep 1, 2026 |
| xorg-x11-server-devel · ol 9 | 0:1.20.11-34.el9_8.3 | ELSA-2026-38486 | Jul 13, 2026 |
| xorg-x11-server-source · RHEL 8 | 0:1.20.11-28.el8_10.3 | RHSA-2026:38487 | Jul 13, 2026 |
| xorg-x11-server-source · RHEL 9 | 0:1.20.11-34.el9_8.3 | RHSA-2026:38486 | Jul 13, 2026 |
| xorg-x11-server-source · almalinux 8 | 1.20.11-28.el8_10.3 | ALSA-2026:38487 | Jul 13, 2026 |
| xorg-x11-server-source · almalinux 9 | 1.20.11-34.el9_8.3 | ALSA-2026:38486 | Jul 13, 2026 |
| xorg-x11-server-source · amzn 2023 | 21.1.13-5.amzn2023.0.11 | ALAS2023-2026-1943 | Jul 20, 2026 |
| xorg-x11-server-source · ol 8 | 0:1.20.11-28.el8_10.3 | ELSA-2026-38487 | Sep 1, 2026 |
| xorg-x11-server-source · ol 9 | 0:1.20.11-34.el9_8.3 | ELSA-2026-38486 | Jul 13, 2026 |
| xwayland · Debian 14 | 2:24.1.13-1 | DEBIAN-CVE-2026-55999 | Jul 8, 2026 |
| xwayland · opensuse-leap 16.0 | 24.1.6-160000.6.1 | OPENSUSE-SU-2026:21283-1 | Jul 10, 2026 |
| xwayland · sles 15.7 | 24.1.5-150700.3.22.1 | SUSE-SU-2026:2787-1 | Jul 8, 2026 |
| xwayland · sles 16.0 | 24.1.6-160000.6.1 | SUSE-SU-2026:22617-1 | Jul 10, 2026 |
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