CVE-2026-41091 | Microsoft Defender Elevation of Privilege Vulnerability

Exp

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

Published: 2026-05-20 Last update: 2026-06-17 Assigner: [email protected] Source: [email protected]
NVD Status：Analyzed，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2026-41091 is rated Critical Active Threat (94.2/100): CVSS High severity, with high exploitation likelihood (EPSS 8.37%, 94th percentile). CISA KEV confirms active exploitation (added 2026-05-20) affecting Microsoft / Defender. a weakness (CWE-59) Unauthenticated remote administrative access may be possible. EPSS rose +7.20% over the last day, indicating growing attacker interest. The CISA remediation deadline has passed—treat as an emergency patch priority.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

CISA KEV Record for CVE-2026-41091

Name: Microsoft Defender Link Following Vulnerability · CISA KEV detail

Exploit added: 2026-05-20

Action due: 2026-06-03

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.

Exploit prediction scoring system (EPSS) score for CVE-2026-41091

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-23 1.17% 8.37% +7.20%
2 2026-06-15 8.06% 1.17% -6.89%
3 2026-06-12 — 8.06% —

Full EPSS history (13 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-41091

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.8 3.1 HIGH
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H Click to expand
Attack vector (AV:L)
They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 1.8 5.9 [email protected]

Weakness enumeration for CVE-2026-41091

GitHub Security Advisory for CVE-2026-41091

GHSA-h776-j9jw-992p · Severity: high — Improper link resolution before file access ('link following') in Microsoft Defender allows an...

Affected software / configurations for CVE-2026-41091

Vendor Product Version Raw CPE
microsoft malware_protection_engine >= 1.1.26030.3008, < 1.1.26040.8 cpe:2.3:a:microsoft:malware_protection_engine:*:*:*:*:*:*:*:*

References for CVE-2026-41091

cvelogic Threat Intelligence