CVE-2026-41091
Published: May 20, 2026· Updated: May 20, 2026
Official Description
Improper link resolution before file access ('link following') in Microsoft Defender allows an authorized attacker to elevate privileges locally.
Technical Analysis
CVE-2026-41091 requires local access, meaning attackers must already have a foothold on the target system.
Exploitation requires low privileges, which limits the exposure to scenarios where an attacker has already gained initial access.
A successful exploit results in complete confidentiality breach (data exposure), full integrity compromise (data manipulation), availability disruption (denial of service), with a CVSS base score of 7.8.
CISA has added CVE-2026-41091 to the Known Exploited Vulnerabilities (KEV) catalog, confirming active exploitation in the wild. U.S. federal agencies are required to patch this within the mandated timeframe, and all organizations should treat remediation as urgent.
CVSS v3.1 Vector Breakdown
Affected Vendors & Products
Exploit & PoC Resources
Official Patches & Advisories
News & Research Mentioning CVE-2026-41091
Microsoft has disclosed that a privilege escalation and a denial-of-service flaw in Defender has come under active exploitation in the wild. The former, tracked as CVE-2026-41091, is rated 7.8 on the CVSS scoring system. Successful exploitation of the flaw could allow an attacker to gain SYSTEM privileges. "Improper link resolution before file access ('link following') in Microsoft Defender [xlite_meta score:56 src:The Hacker News xlite_fp:65f4313dd2233587a512159f983461fcc08b759a00d53da75c960bedc8f2761e]
CISA has added seven new vulnerabilities to its Known Exploited Vulnerabilities (KEV) Catalog, based on evidence of active exploitation. CVE-2008-4250 Microsoft Windows Buffer Overflow Vulnerability CVE-2009-1537 Microsoft DirectX NULL Byte Overwrite Vulnerability CVE-2009-3459 Adobe Acrobat and Reader Heap-Based Buffer Overflow Vulnerability CVE-2010-0249 Microsoft Internet Explorer Use-After-Free Vulnerability CVE-2010-0806 Microsoft Internet Explorer Use-After-Free Vulnerability CVE-2026-41091 Microsoft Defender Elevation of Privilege Vulnerability CVE-2026-45498 Microsoft Defender Denial of Service Vulnerability These types of vulnerabilities are frequent attack vectors for malicious cyber actors and pose significant risks to the federal enterpri [xlite_meta score:63 src:CISA Alerts xlite_fp:75dcd75a228f8d5c7ae44bdeae2e67fd9beb1fc70823543e8283fbf2ed7bb584]
All References (2)
Quick Facts
Recommended Actions
- →Apply vendor patches immediately
- →Monitor CVE-2026-41091 in threat intel feeds
- →Review IDS/IPS signatures for exploitation attempts
- !CISA KEV: Federal agencies must patch per BOD 22-01 timeline
- !Active exploitation confirmed — treat as P1