Ubuntu fixes libXtst denial-of-service flaws from malicious X servers
Original title: USN-8939-1: libXtst vulnerabilities
CVE-2026-94286 can crash libXtst clients; CVE-2016-7951 is an out-of-bounds issue limited to Ubuntu 16.04 LTS.
Ubuntu published USN-8939-1 for libXtst. A malicious X server can crash clients by mishandling certain RECORD replies (CVE-2026-94286). A separate memory flaw, CVE-2016-7951, can cause out-of-bounds access and denial of service, and Ubuntu says it affects only 16.04 LTS. The notice is cut off while describing another reply-handling issue.
Unconfirmed: The notice snippet ends before fully describing a further reply-handling issue.
- CVE-2026-94286 is a client crash via malformed RECORD replies.
- CVE-2016-7951 affects only Ubuntu 16.04 LTS.
- The snippet does not list fixed package versions.
Impact: Denial of service in libXtst clients
| Product | Affected |
|---|---|
| Ubuntu libXtst | — |
| Ubuntu libXtst | Ubuntu 16.04 LTS |
- 1.Install the libXtst updates published in USN-8939-1.
Vulnerabilities mentioned
All| CVE | Vulnerability | CVSS | EPSS | Signals | Published |
|---|---|---|---|---|---|
| CVE-2016-7951 | Multiple integer overflows in X.org libXtst before 1.2.3 allow remote X servers to trigger out-of-bounds memory access operations by leveraging the lack of… | 9.8 | 2% | ||
| CVE-2026-94286 | Out-of-bounds read in libXtst RECORD reply parser | 7.1 | — |
From the original article
It was discovered that libXtst did not properly handle certain RECORD replies from the X server. A malicious X server could possibly use this issue to cause libXtst clients to crash, resulting in a denial of service. (CVE-2026-94286) Tobias Stoeckmann discovered that libXtst did not properly handle certain memory operations.
ubuntu.com
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