Microsoft Defender Insufficient Granularity of Access Control Vulnerability

[ Why it matters ]Priority signals

• Exploited in the wild: on CISA's Known Exploited Vulnerabilities list since 2026-04-22
• Known to be used in ransomware campaigns

[ Description ]Official description

Insufficient granularity of access control in Microsoft Defender allows an authorized attacker to elevate privileges locally.

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

[ Fixes ]Fixes and patches

CISA required action (US federal deadline 6 May 2026): Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

No fix or interim patch is linked from our sources yet. Check the vendor references below and limit exposure of affected systems until a fix is available.

[ References ]References

• msrc.microsoft.com/update-guide/vulnerability/CVE-2026-33825Vendor Advisory
• www.cisa.gov/known-exploited-vulnerabilities-catalogUS Government Resource
• www.huntress.com/blog/nightmare-eclipse-intrusionThird Party Advisory