Quick answers
- Is CVE-2026-109088 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-109088 being exploited in the wild.
- How severe is CVE-2026-109088?
- Medium severity, with a CVSS score of 6.5, published 27 October 2026.
- Which products and versions are affected?
- Freedesktop libXtst before 1.2.6.
- Is there a fix for CVE-2026-109088?
- Yes: fixed in libXtst 1.2.6. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
- How is CVE-2026-109088 attacked?
- It is attacked over the network, in a software library.
- Am I affected by CVE-2026-109088?
- Check whether you run Freedesktop libXtst at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.
How to fix
- Fixed in: libXtst 1.2.6
Technical details
The parse_reply_call_callback function in libXtst versions before 1.2.6 fails to properly validate zero-progress RECORD reply elements from a malicious server. An attacker controlling an X server can send malformed EnableContext replies with either zero-length BIG-REQUESTS or undefined category bytes that cause the parsing loop to hang indefinitely. This results in a denial of service as the application remains locked in a busy loop.
Affected products
- freedesktop libXtst before 1.2.6
Timeline
- 2026-10-27: disclosed
- 2026-10-27: advisory