Published Oct 27, 2026Sources checked Oct 29, 2026
6.5MEDIUMCVSS out of 10
What this means
Review the available evidence
CVE-2026-109088 and is rated Medium severity with a CVSS score of 6.5. It is not in the current CISA KEV record we collected. That does not prove exploitation has not occurred.
What to do next
Remediation and response
Microsoft Security Response Center guidance
Vendor revision: Oct 29, 2026
Release Notes
CISA KEVNot listedBased on the latest collected catalog
EPSS0.3%Estimated 30-day exploitation probability
Ransomware useNot markedCISA KEV ransomware field
Threat actors0Source-linked actor relationships
Overview
What is 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.