Microsoft Defender Link Following Vulnerability

[ Why it matters ]Priority signals

• Exploited in the wild: on CISA's Known Exploited Vulnerabilities list since 2026-05-20

[ Description ]Official description

Improper link resolution before file access ('link following') in Microsoft Defender allows an authorized attacker to elevate privileges locally.

CISA: Microsoft Defender contains a link following vulnerability that allows an authorized attacker to elevate privileges locally.

[ Fixes ]Fixes and patches

CISA required action (US federal deadline 3 Jun 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-2026-41091Vendor Advisory
• www.cisa.gov/known-exploited-vulnerabilities-catalogThird Party AdvisoryUS Government Resource