CVE-2026-41091

HIGH7.8

CISA KEV

Published 2026-05-20 · Updated 2026-07-24 · Source secure@microsoft.com

Summary

CVE-2026-41091 is a high-severity (CVSS 7.8) vulnerability in Microsoft Defender. CISA added it to the Known Exploited Vulnerabilities catalog on May 20, 2026, which means exploitation in the wild has been confirmed; US federal agencies had to remediate it by June 3, 2026. CISA does not currently list it as used in ransomware campaigns. Microsoft has 390 vulnerabilities in the KEV catalog, 117 of them linked to ransomware.

All 390 known-exploited Microsoft vulnerabilities →

Description

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

CVSS vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CWE-59

CISA Known-Exploited Vulnerability

Product: Microsoft — Defender

Name: Microsoft Defender Link Following Vulnerability

Date added: 2026-05-20 · Due: 2026-06-03

Required action: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

References

View on NVD

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