CVE-2023-6377: Xorg-x11-server: out-of-bounds memory reads/writes in xkb button actions

Severity: high (CVSS 7.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.6% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2023-12-13 · updated 2026-06-23
Weakness: CWE-125

Description

A flaw was found in xorg-server. Querying or changing XKB button actions such as moving from a touchpad to a mouse can result in out-of-bounds memory reads and writes. This may allow local privilege escalation or possible remote code execution in cases where X11 forwarding is involved.

Affected products

Debian Linux: 10.0, 11.0, 12.0
RedHat Enterprise Linux Eus: 9.2
Kaspersky TigerVNC: all versions
xorg-x11-server: before 21.1.10 — fixed in 21.1.10
X.Org xwayland: before 23.2.3 — fixed in 23.2.3

How to fix

Upgrade to a fixed version: xorg-x11-server 21.1.10; X.Org xwayland 23.2.3. Check the vendor advisory for mitigations.

References

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