CVE-2023-6816: Debian Linux

Critical severity, CVSS 9.8. EPSS: 2.1% chance of exploitation in the next 30 days.

A flaw was found in X.Org server. Both DeviceFocusEvent and the XIQueryPointer reply contain a bit for each logical button currently down. Buttons can be arbitrarily mapped to any value up to 255, but the X.Org Server was only allocating space for the device's particular number of buttons, leading to a heap overflow if a bigger value was used.

Affected products

• Debian Debian Linux: version 10.0 only
• Fedoraproject Fedora: version 39 only
• Red Hat Enterprise Linux Desktop: version 7.0 only
• Red Hat Enterprise Linux Server: version 7.0 only
• Red Hat Enterprise Linux Workstation: version 7.0 only
• X.org X Server: before 21.1.11 (fixed in 21.1.11)
• X.org Xwayland: before 23.2.4 (fixed in 23.2.4)

Published 2024-01-18. Last modified 2026-06-17.