CVE-2026-109088: X.org libXtst · Infinite Loop
Affects X.org libXtstSource CVE Database V5
Not known to be exploited · CVSS 6.5 Medium : upgrade to 1.2.6 when convenient.
Data as of 27 Oct 2026, 17:24 UTC
- Patch
- Available – fixed in 1.2.6
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 27 Oct 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Upgrade libXtst and the Debian debian/libxtst package to 1.2.6.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| X.orglibXtst | Affected
| Fixed in
|
Debiandebian/libxtstpkg:deb/debian/libxtstOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
Upgrade libXtst to version 1.2.6 or later, where this infinite loop vulnerability is fixed. No other mitigation is required as the fix is available.
Description
CVE-2026-109088 is an infinite loop vulnerability in the X.org libXtst library versions prior to 1.2.6. A malicious X server can send malformed RECORD EnableContext replies that cause a client using the parse_reply_call_callback function to enter an endless loop, potentially leading to denial of service.