CVEs / CVE-2026-41091
CVE-2026-41091: Microsoft Defender Link Following Vulnerability
- Known exploited in the CISA KEV catalog since 20 May 2026
- high 7.8 CVSS 3.1 (from the CNA)
- EPSS 8.2% chance of exploitation in the next 30 days, higher than 94% of CVEs (30 Oct 2026)
- Last changed at its sources
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Summary
Microsoft Defender contains a link following vulnerability that allows an authorized attacker to elevate privileges locally.
Description
Improper link resolution before file access ('link following') in Microsoft Defender allows an authorized attacker to elevate privileges locally.
Affected and fixed versions
| Product | Affected | Fixed in |
|---|---|---|
| Microsoft Microsoft Malware Protection Engine | from 1.1.0.0, before 1.1.26040.8 | 1.1.26040.8 |
Exploitation
| In CISA KEV since | 20 May 2026 |
|---|---|
| Due date for US federal agencies | 3 Jun 2026 |
| Used in ransomware campaigns | Unknown |
| 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. |
Severity
| CVSS 3.1 | 7.8 highCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HScored by the CNA ([email protected]) |
|---|---|
| Weakness | CWE-59 |
References
- CVE-2026-41091 on NVD
- CVE-2026-41091 in the CISA KEV catalog
- https://msrc.microsoft.com/update-guide/en-US/vulnerability/CVE-2026-41091 (cited by CISA)
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-41091 Vendor Advisory
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-41091 Third Party Advisory, US Government Resource
Sources
Exploitation status from the CISA Known Exploited Vulnerabilities catalog. EPSS scores from FIRST. Descriptions, severity and references from the National Vulnerability Database. Open-source package versions from OSV (CC-BY 4.0). Text is shown as each source states it; Stackurity does not edit it. Check the vendor's advisory before acting.
This product uses data from the NVD API but is not endorsed or certified by the NVD.