A use-after-free flaw was found in the X.Org X server and Xwayland in SyncChangeCounter(). A client that sets up multiple SyncCounters can trigger a use-after-free when destroying those counters via a second client connection while changing those counters. This may be used to crash the server, or for privilege escalation if the X server runs as root.
CVSS Details
- CVSS 3.1 Base Score: 7.8
- CVSS 3.1 Vector: (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H)
Covered by Rapid7
| Product | Vendor Advisory | Solution File | Added | Published |
|---|---|---|---|---|
| Alma_linux | — | Upgrade xorg-x11-server-commonUpgrade tigervnc-server-moduleUpgrade xorg-x11-server-sourceUpgrade tigervnc-iconsUpgrade tigervnc-licenseUpgrade xorg-x11-server-XdmxUpgrade xorg-x11-server-develUpgrade xorg-x11-server-XvfbUpgrade xorg-x11-server-XephyrUpgrade tigervnc-server-minimalUpgrade xorg-x11-server-XnestUpgrade tigervncUpgrade tigervnc-serverUpgrade xorg-x11-server-XorgUpgrade xorg-x11-server-Xwayland-develUpgrade xorg-x11-server-XwaylandUpgrade tigervnc-selinux | Jun 17, 2026 | Jun 17, 2026 |
| Amazon Linux Ami 2 | — | Upgrade xorg-x11-server-XnestUpgrade xorg-x11-server-XorgUpgrade xorg-x11-server-XwaylandUpgrade xorg-x11-server-commonUpgrade xorg-x11-server-sourceUpgrade xorg-x11-server-develUpgrade xorg-x11-server-XdmxUpgrade xorg-x11-server-debuginfoUpgrade xorg-x11-server-XvfbUpgrade xorg-x11-server-Xephyr | Jun 16, 2026 | Jun 16, 2026 |
| Amazon_linux_2023 | — | Upgrade xorg-x11-server-XwaylandUpgrade tigervnc-server-module-debuginfoUpgrade xorg-x11-server-debugsourceUpgrade tigervnc-iconsUpgrade xorg-x11-server-XorgUpgrade tigervnc-server-minimalUpgrade tigervnc-debuginfoUpgrade tigervnc-server-moduleUpgrade xorg-x11-server-Xorg-debuginfoUpgrade tigervnc-selinuxUpgrade xorg-x11-server-Xwayland-develUpgrade xorg-x11-server-debuginfoUpgrade tigervnc-serverUpgrade xorg-x11-server-Xwayland-debuginfoUpgrade tigervnc-debugsourceUpgrade tigervnc-licenseUpgrade tigervnc-server-debuginfoUpgrade xorg-x11-server-Xvfb-debuginfoUpgrade xorg-x11-server-XvfbUpgrade xorg-x11-server-XnestUpgrade xorg-x11-server-XephyrUpgrade tigervnc-server-minimal-debuginfoUpgrade xorg-x11-server-Xnest-debuginfoUpgrade xorg-x11-server-sourceUpgrade xorg-x11-server-commonUpgrade xorg-x11-server-Xephyr-debuginfoUpgrade xorg-x11-server-develUpgrade xorg-x11-server-Xwayland-debugsourceUpgrade tigervnc | Jun 15, 2026 | Jun 5, 2026 |
| Debian | — | Upgrade xorg-server | Jul 23, 2026 | Jul 23, 2026 |
| Freebsd | — | Upgrade xwaylandUpgrade xorg-server | Jun 15, 2026 | Jun 1, 2026 |
| Gentoo Linux | — | Upgrade x11-base/xorg-server.Upgrade x11-base/xwayland. | Aug 17, 2026 | Aug 17, 2026 |
| Redhat_linux | — | Upgrade tigervnc-debuginfoUpgrade xorg-x11-server-Xwayland-debugsourceUpgrade xorg-x11-server-XvfbUpgrade xorg-x11-server-Xvfb-debuginfoUpgrade xorg-x11-server-XdmxUpgrade tigervnc-server-debuginfoUpgrade tigervncUpgrade xorg-x11-server-Xorg-debuginfoUpgrade tigervnc-serverUpgrade xorg-x11-server-XephyrUpgrade tigervnc-licenseUpgrade xorg-x11-server-develUpgrade xorg-x11-server-Xnest-debuginfoNo solution existsUpgrade xorg-x11-server-Xephyr-debuginfoUpgrade xorg-x11-server-Xwayland-debuginfoUpgrade xorg-x11-server-sourceUpgrade tigervnc-server-appletUpgrade tigervnc-server-module-debuginfoUpgrade xorg-x11-server-XnestUpgrade tigervnc-selinuxUpgrade xorg-x11-server-debuginfoUpgrade xorg-x11-server-XwaylandUpgrade xorg-x11-server-Xwayland-develUpgrade xorg-x11-server-XorgUpgrade tigervnc-server-minimal-debuginfoUpgrade tigervnc-iconsUpgrade tigervnc-debugsourceUpgrade tigervnc-server-minimalUpgrade xorg-x11-server-commonUpgrade tigervnc-server-moduleUpgrade xorg-x11-server-Xdmx-debuginfoUpgrade xorg-x11-server-debugsource | Jun 19, 2026 | Jun 2, 2026 |
| Rocky_linux | — | Upgrade xorg-x11-server-debuginfoUpgrade tigervnc-serverUpgrade xorg-x11-server-develUpgrade xorg-x11-server-XdmxUpgrade tigervnc-server-module-debuginfoUpgrade xorg-x11-server-Xvfb-debuginfoUpgrade xorg-x11-server-Xdmx-debuginfoUpgrade tigervnc-server-minimalUpgrade xorg-x11-server-Xorg-debuginfoUpgrade tigervnc-server-debuginfoUpgrade xorg-x11-server-Xnest-debuginfoUpgrade tigervncUpgrade tigervnc-server-moduleUpgrade tigervnc-server-minimal-debuginfoUpgrade xorg-x11-server-XephyrUpgrade xorg-x11-server-debugsourceUpgrade xorg-x11-server-Xwayland-debuginfoUpgrade xorg-x11-server-XorgUpgrade xorg-x11-server-XvfbUpgrade xorg-x11-server-XwaylandUpgrade xorg-x11-server-Xephyr-debuginfoUpgrade xorg-x11-server-Xwayland-develUpgrade xorg-x11-server-commonUpgrade tigervnc-debuginfoUpgrade xorg-x11-server-Xwayland-debugsourceUpgrade xorg-x11-server-XnestUpgrade tigervnc-debugsource | Jun 22, 2026 | Jun 19, 2026 |
Prioritise with Active Threat Intelligence
With curated Threat Intelligence, you can see which vulnerabilities truly put you at risk, prioritize what matters most, and act before attackers do.
Explore Intelligence Hub