Detecting CVE-2026-20929: Kerberos Authentication Relay via CNAME Abuse
CVE-2026-20929, a vulnerability with a CVSS of 7.5 that was patched in the January 2026 Patch Tuesday update, enables attackers to exploit Kerberos authentication relay through DNS CNAME record abuse. This blog focuses on detecting one particularly impactful attack vector: relaying authentication to Active Directory Certificate Services (AD CS) to enroll certificates for user accounts, as detailed in recent research.