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VulnerabilityPublished Updated

CVE-2026-41091: Microsoft Malware Protection Engine · Link Following

Affects Microsoft Malware Protection EngineSource CVE Database V5

0
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Exploited in the wild · KEV due 3 Jun 2026 · 8% EPSS : upgrade to 1.1.26040.8 now.

Data as of 30 Oct 2026, 11:52 UTC

CVSS 3.1 base score
7.8High
How severe the flaw is on the 0–10 CVSS scale.
KEV deadline
 US federal agencies must patch by this date; a sensible deadline for everyone else. Other KEV due dates
EPSS
8.2% chance of exploitation in 30 days – higher than 94% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 1.1.26040.8
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

Exploitation evidence

t = 0 is the CVE’s publication on cve.org

  1. Disclosed: evidence found.

    CVE published 20 May 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: evidence found.

    Public exploit code: GitHub proofs of concept

  4. Exploited in the wild: evidence found.

    Listed in CISA KEV the same day as disclosure

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

Timeline

  1. CVE ID reserved

    by Microsoft Corporation

    , 34 days before disclosure

  2. CVE published

    on cve.org

    , t = 0

  3. In Threat Radar

    record ingested

    , 10 minutes after disclosure

  4. , the same day as disclosure

  5. KEV remediation due

    US federal deadline

    , 14 days after disclosure

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), GitHub proofs of concept, CISA KEV (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 30 Oct 2026.

What to do

Upgrade Microsoft Malware Protection Engine to 1.1.26040.8.

Affected software

ProductAffectedFixed in
MicrosoftMicrosoft Malware Protection EngineAffected
  • >=1.1.0.0 <1.1.26040.8
Fixed in
  • 1.1.26040.8

Description

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

References

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