CVE-2026-88648 and is rated Low severity with a CVSS score of 3.7. 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 13, 2026
Release Notes
CISA KEVNot listedBased on the latest collected catalog
EPSS0.2%Estimated 30-day exploitation probability
Ransomware useNot markedCISA KEV ransomware field
Threat actors0Source-linked actor relationships
Overview
What is CVE-2026-88648?
Incomplete X.509 implementation in GnuTLS v3.8.13 allows attackers controlling a subordinate Certificate Authority to bypass cross-domain PKI restrictions and issue unauthorized certificates.