CVE-2026-88806
HighCVSS 7.5Exploitation Probability (EPSS)
Low risk10th percentile - higher than 10% of all known CVEs
Summary
A malicious X server could exploit a buffer overflow in libX11 before 1.8.14 during handling of XkbGetMap overflowing the key_sym_map.
Risk Assessment
A malicious X server could exploit the buffer overflow to execute code or cause a crash in attached X clients. Risk applies to environments connecting to untrusted X servers.
Recommendation
Upgrade libX11 to version 1.8.14 or later. Avoid connecting to untrusted X servers.
Other vulnerabilities in libX11
See all- CVE-2026-94285Medium
An out-of-bounds read in libX11's byte-oriented codeset parser before 1.8.14 could be used by malicious X servers to crash attached X clients.
- CVE-2026-94284Medium
An out-of-bounds read vulnerability in libX11's XIM trigger-key registration parser before 1.8.14 could be used by malicious X servers to crash attached X clients.
- CVE-2026-94283Medium
An out-of-bounds read vulnerability in libX11's XIM attribute parser before 1.8.14 could be used by malicious X servers to crash attached X clients.
- CVE-2023-3138High
A vulnerability was found in libX11 due to a lack of checks on values passed to functions in src/InitExt.c. These values are used as array indexes, which can lead to overwriting other parts of the Display structure, potentially causing the client to crash due to memory corruption.
Original NVD description (English source)
A malicious X server could exploit a buffer overflow in libX11 before 1.8.14 during handling of XkbGetMap overflowing the key_sym_map.
Vulnerability data from NVD (NIST) · CISA KEV · EPSS