CVE-2026-41091: Microsoft Defender Link Following Vulnerability
Vulnerability summary
CVE-2026-41091 is a high (CVSS 7.8) Link Following vulnerability in Microsoft Defender. It is known to be exploited: CISA lists it, first on 20-05-2026. EPSS estimates a 0.44% chance of exploitation in the next 30 days, higher than 37.1% of scored vulnerabilities.
Timeline
- 20-05-2026PublishedVulnerability first disclosed.
- 20-05-2026Added to CISA KEVMicrosoft Defender Link Following Vulnerability
- 03-06-2026CISA remediation dueApply mitigations per vendor instructions.
- 10-08-2026Last modifiedVulnerability information updated.
Description
Improper link resolution before file access ('link following') in Microsoft Defender allows an authorized attacker to elevate privileges locally.
CVSS metrics
2 scores · 2 sources · 1 version- NVDNIST7.8HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
EPSS trend
Probability
0.44%
Chance of exploitation in the next 30 days
Percentile
37%
Versus all other CVEs
30-day change
-7.76 pp
From 8.20% on 19-09-2026
Known exploited
Compare KEV catalogs
CISA KEVListed- Added
- 20-05-2026
- Federal due date
- 03-06-2026
CISA 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. msrc.microsoft.com/update-guide/en-US/vulnerability/CVE-2026-41091 nvd.nist.gov/vuln/detail/CVE-2026-41091
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
Microsoft2 products
- malware_protection_engine≥ 1.1.26030.3008, < 1.1.26040.8
- microsoft malware protection engine≥ 1.1.0.0, < 1.1.26040.8
1 vendor · 2 products
References
2 links
- www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-41091Government ResourceThird Party AdvisoryUS Government Resource