CVE-2026-33825

Insufficient Granularity of Access Control in Microsoft Defender. CISA confirmed attackers exploit it and added it to its Known Exploited Vulnerabilities catalog on 22 April 2026.

Product
Microsoft Defender
Added to CISA's catalog
Federal fix-by date
Ransomware
Known to be used in ransomware

CISA’s description.

Microsoft Defender contains an insufficient granularity of access control vulnerability that could allow an authorized attacker to escalate privileges locally.

Every flaw CISA confirmed exploited in the last 30 days is on the exploit watch. This is not security advice. Check the vendor’s advisory before acting. From CISA’s catalog of 4 November 2026.