HOMEVULNERABILITIESCVE-2026-41091
HIGHCISA KEVIN THE WILD

CVE-2026-41091

Published: May 20, 2026· Updated: May 20, 2026

7.8
CVSS v3.1
EPSS:4.53%probability of exploitation in 30 daysPercentile:89.3th

Official Description

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

NVD Source

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

Exploitability
Attack VectorLocal
Attack ComplexityLow
Privileges Req.Low
User InteractionNone
ScopeUnchanged
Impact
ConfidentialityHigh
IntegrityHigh
AvailabilityHigh
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected Vendors & Products

Microsoft1 product
malware protection engine
Source: NVD CPE · 1 total CPE entries

Exploit & PoC Resources

ACTIVE EXPLOITATIONConfirmed exploitation in the wild
External links open in a new tab. Always verify in a controlled environment before use.

Official Patches & Advisories

News & Research Mentioning CVE-2026-41091

Microsoft Warns of Two Actively Exploited Defender Vulnerabilities
The Hacker News· May 21, 2026

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 Adds Seven Known Exploited Vulnerabilities to Catalog
CISA Alerts· May 20, 2026

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

CVE IDCVE-2026-41091
CVSS Score7.8 / 10
SeverityHIGH
CISA KEVYES — Active Exploitation
ExploitIN THE WILD
EPSS (30d)4.53%
Affected1 vendor
PublishedMay 20, 2026

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
Data sourced from NVD (NIST), CISA KEV, and EPSS (FIRST). Analysis generated by CTIWATCH.COM. CVE data is provided under the NVD usage policy.