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High 7.8Known exploited (CISA KEV)Published May 20, 2026
CVE-2026-41091Microsoft Defender Elevation of Privilege Vulnerability
Updated under an hour ago ()
Does this affect you?
It affects Microsoft Malware Protection Engine. Add what you run to find out whether that includes you.
CISA lists it as known exploited since May 20, 2026; federal agencies had to remediate by Jun 3, 2026. Treat that date as your deadline.
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Improper link resolution before file access ('link following') in Microsoft Defender allows an authorized attacker to elevate privileges locally.
- CVSS
- 7.8 HIGH (v3.1, CNA)CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C
- Weakness (CWE)
- CWE-59
- Known exploited
- Added to CISA KEV May 20, 2026; federal remediation due Jun 3, 2026Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
- EPSS (exploitation in the next 30 days)
- 0.44% (percentile 37)
- Assigned by
- microsoft
- NVD analysis
- Analyzed
- Record last updated
- Aug 10, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
Microsoft Microsoft Malware Protection Engine microsoft:malware_protection_engine (from the name) | from 1.1.0.0 before 1.1.26040.8 | CNA record |
microsoft malware_protection_engine microsoft:malware_protection_engine | from 1.1.26030.3008 before 1.1.26040.8 | NVD |
References
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-41091vendor-advisory, patch
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-41091third-party-advisory, us-government-resource
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.