Actively exploited · Published May 20, 2026 · Assigned by microsoft
CVE-2026-41091Microsoft Defender Elevation of Privilege Vulnerability
High 7.8 Exploited
In plain English
A high-severity security flaw in Microsoft Malware Protection Engine from Microsoft. Attackers are actively exploiting it in the wild (listed by CISA on May 20, 2026). The chance it is exploited in the next 30 days is estimated at 8.2% (higher than 95% of all known vulnerabilities). Ready-made attack tooling exists: public proof-of-concept code. Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
CISA guidance
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
Federal agencies must remediate by Jun 3, 2026.
Official description
Improper link resolution before file access ('link following') in Microsoft Defender allows an authorized attacker to elevate privileges locally.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Microsoft | Microsoft Malware Protection Engine | 1.1.0.0 – before 1.1.26040.8 |
Weakness: CWE-59 · Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C
References
- Microsoft Defender Elevation of Privilege Vulnerability vendor-advisory, patch
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-41091 government-resource