CVE-2025-26597: Xorg: xwayland: buffer overflow in xkbchangetypesofkey()

Severity: high (CVSS 7.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2025-02-25 · updated 2026-06-29
Weakness: CWE-119

Description

A buffer overflow flaw was found in X.Org and Xwayland. If XkbChangeTypesOfKey() is called with a 0 group, it will resize the key symbols table to 0 but leave the key actions unchanged. If the same function is later called with a non-zero value of groups, this will cause a buffer overflow because the key actions are of the wrong size.

Affected products

Red Hat Enterprise Linux: 7.0, 8.0, 9.0
Kaspersky TigerVNC: all versions
xorg-x11-server: before 21.1.16 — fixed in 21.1.16
X.Org xwayland: before 24.1.6 — fixed in 24.1.6

How to fix

Upgrade to a fixed version: xorg-x11-server 21.1.16; X.Org xwayland 24.1.6. Check the vendor advisory for mitigations.

References

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