Microsoft Defender Privilege Escalation Vulnerability WID-SEC-2026-1099

CERT-Bund published security advisory WID-SEC-2026-1099 disclosing a vulnerability in Microsoft Defender Antimalware Platform that allows a local attacker to escalate privileges to Administrator level. The vulnerability has a CVSS Base Score of 7.8 (high) and is not remotely exploitable. Organizations running Microsoft Defender on Windows systems should apply available mitigations immediately and assess their exposure. This advisory affects any entity using Microsoft Defender for malware detection, particularly those with multi-user Windows environments where privilege separation is critical for security posture.

Affected parties should prioritize applying vendor-provided patches or workarounds, review local user permissions on Windows systems, and monitor for Microsoft's security updates addressing this vulnerability. The non-remote attack vector means exploitation requires existing local access, but the high CVSS score indicates severe potential impact if exploited.