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Ubuntu Security NoticesUSN-8913-1

USN-8913-1: libx11 vulnerabilities

Severity not listed 4 CVEs Published Oct 12, 2026 at 12:53 PM UTC

Summary

Adam Bedard discovered that libx11 incorrectly handled certain XKB keyboard map replies. If a user were tricked into connecting to a malicious X server, a remote attacker could possibly use this issue to cause libx11 to crash, resulting in a denial of service, or possibly execute arbitrary code. (CVE-2026-88806)

It was discovered that libx11 incorrectly handled certain X Input Method (XIM) messages. If a user were tricked into connecting to a malicious X server, a remote attacker could possibly use these issues to cause libx11 to crash, resulting in a denial of service. (CVE-2026-94283, CVE-2026-94284)

It was discovered that libx11 incorrectly handled converting certain multibyte text. An attacker could possibly use this issue to cause libx11 to crash, resulting in a denial of service. (CVE-2026-94285)

Products covered

A separate affected-products list was not included in the collected bulletin.

Remediation

Separate remediation guidance was not included in the collected bulletin.

CVEs in this advisory 4

Updates

  1. Published by Ubuntu

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  2. Added to SecurityAlert

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  3. Confirmed at the source

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