Client crash via out-of-bounds RECORD reply read
Published Sep 28, 2026 · Updated Sep 28, 2026
Out-of-bounds read in X.Org libXtst before 1.2.6 allows remote attackers to crash connected X clients via malformed RECORD replies. The RECORD reply parser reads outside the received reply buffer while processing data from an X server; the exact failed bounds check is not public. A client must connect to an attacker-controlled X server and exercise the RECORD extension; the established consequence is a client crash.
Summary
What happened
Out-of-bounds read in X.Org libXtst before 1.2.6 allows remote attackers to crash connected X clients via malformed RECORD replies. The RECORD reply parser reads outside the received reply buffer while processing data from an X server; the exact failed bounds check is not public. A client must connect to an attacker-controlled X server and exercise the RECORD extension; the established consequence is a client crash.
The record
- CVE
- CVE-2026-94286
- Published
- Sep 28, 2026
- Updated
- Sep 28, 2026
- Vendor
- The X11 Project
- Product
- libXtst
- Classifications
- T1499.004
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Sep 28, 2026CVE publishedPublication date reported by the CVE source.
- Sep 28, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=0 <1.2.6
What conditions does exploitation require?
What is affected?
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Activity data is delayed. The latest report is Sep 28, 2026.
Weakness, pattern, technique
Public exploit references
No public exploit references are available in this record.
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Technologies
Your stack
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Your stack
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