What is CVE-2026-109088?

CVE-2026-109088 is a medium-severity vulnerability in X.org Libxtst, classified under Loop with Unreachable Exit Condition (Infinite Loop). CVSS score: 6.5/10. Published 2026-10-27.

How severe is CVE-2026-109088?

Medium severity. CVSS v3 base score is 6.5 out of 10.

Vulnerability in X.org Libxtst

CVE-2026-109088

A malicious X server could send malformed RECORD EnableContext reolies that can cause a X client using the parse_reply_call_callback function in libXtst before 1.2.6 to enter a endless loop.

Published 2026-10-27.

CVSS v3 metric

CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H.

EPSS exploit prediction

No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.

Affected products

X.org Libxtst

Weakness classification (CWE)

CWE-835 — Loop with Unreachable Exit Condition (Infinite Loop)

References

gitlab.freedesktop.org/xorg/lib/libxtst/-/merge_requests/11 (patch)

Frequently asked questions

What is CVE-2026-109088?: CVE-2026-109088 is a medium-severity vulnerability in X.org Libxtst, classified under Loop with Unreachable Exit Condition (Infinite Loop). CVSS score: 6.5/10. Published 2026-10-27.
How severe is CVE-2026-109088?: Medium severity. CVSS v3 base score is 6.5 out of 10.