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CVE-2026-109088VulnerabilityPublished

A malicious X server could send malformed RECORD EnableContext reolies that can cause a X client using the

Source GCVE Database

0
Authoritative record:CVE-2026-109088· Medium 6.5

Not known to be exploited · CVSS 6.5 Medium : upgrade to 1.2.6 when convenient.

Data as of 27 Oct 2026, 19:59 UTC

CVSS 3.1 base score
6.5Medium
How severe the flaw is on the 0–10 CVSS scale.
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:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 27 Oct 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq 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

ProductAffectedFixed in
X.orglibXtstAffected
  • <1.2.6
Fixed in
  • 1.2.6
Debiandebian/libxtstpkg:deb/debian/libxtstOther threatsAffected
  • <1.2.6
Fixed in
  • 1.2.6

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

A fix is available in libXtst version 1.2.6 and later. Users and administrators should upgrade to libXtst 1.2.6 or newer to remediate this vulnerability. No other mitigation or workaround is specified.

Description

A vulnerability in libXtst versions before 1.2.6 allows a malicious X server to send malformed RECORD EnableContext replies that cause an X client using the parse_reply_call_callback function to enter an endless loop. This results in a denial of service condition due to resource exhaustion.

References

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