CVE-2026-41091
Microsoft Malware Protection Engine 1.1.26030.3008 – 1.1.26040.8
Raw vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HSummary
CVE-2026-41091 is a high-severity Link Following (CWE-59) vulnerability in Microsoft Malware Protection Engine. Its CVSS base score is 7.8 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Path Interception (T1034); ranked in the top 5% of CVEs by exploit likelihood; CISA has added it to the Known Exploited Vulnerabilities catalog.
The strongest mitigations our analysis identified map to AC-3 (Access Enforcement) and AC-6 (Least Privilege) — see the control section below for these in your framework.
Deeper analysis AI-assisted summary
Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.
CVE-2026-41091 is an improper link resolution vulnerability, also described as a link-following flaw under CWE-59, that affects Microsoft Defender. The issue permits an authorized local attacker to perform unauthorized file access operations that lead to privilege escalation on the affected system, carrying a CVSS 3.1 base score of 7.8 reflecting high impact on confidentiality, integrity, and availability.
An attacker with local access and low privileges can exploit the flaw without user interaction by supplying a malicious link that Microsoft Defender follows before properly validating the target. Successful exploitation grants the attacker elevated rights on the host, enabling further actions such as installing persistent malware or accessing sensitive data.
Microsoft has published remediation guidance through its Security Response Center at the listed MSRC URL, while CISA includes the CVE in its Known Exploited Vulnerabilities catalog, indicating that federal agencies must apply available mitigations. The EPSS score rose from a low baseline to a peak of 0.1210 the day after disclosure before receding to the current value of 0.0821, showing measurable post-publication exploitation interest.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-31101
Vulnerability Data
Improper link resolution before file access ('link following') in Microsoft Defender allows an authorized attacker to elevate privileges locally.
- CWE(s)
- KEV Date Added
- 20 May 2026
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
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V15.4.2
Mitigating Controls (NIST 800-53 r5) AI
Proper enforcement of access authorizations on the resolved target resource stops a link from reaching an unintended object.
Least-privilege limits the damage an attacker can cause after following an unintended link.
Validating file-name inputs can reject or canonicalize names that resolve to links before access occurs.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Secure SDLC practices directly require code to validate paths and avoid unsafe link following.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
Security testing can detect link-following flaws before release.
Secure SDLC practices can mandate link-resolution checks and canonicalization before file access.
Application security requirements can explicitly require safe handling of symbolic links and path traversal.
Secure architecture principles include input validation and safe file-access design patterns.
Secure coding standards directly address canonicalization and symlink attacks during implementation.
Access-control rules can limit which files are reachable, reducing exposure to malicious links.