Raw vector
CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:HCVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.
Summary
CVE-2025-21399 is a high-severity Untrusted Search Path (CWE-426) vulnerability in Microsoft Edge Update. Its CVSS base score is 7.4 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Path Interception (T1034); ranked at the 50th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.
The strongest mitigations our analysis identified map to CM-6 (Configuration Settings) and CM-7 (Least Functionality) — 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-2025-21399 is an elevation of privilege vulnerability in the update component of Microsoft Edge (Chromium-based). Published on 2025-01-17, it carries a CVSS v3.1 base score of 7.4 (AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H) and maps to CWE-426 (Untrusted Search Path).
The vulnerability can be exploited by a local attacker requiring no privileges or user interaction, though it demands high attack complexity. Successful exploitation enables elevation of privileges, resulting in high impacts to confidentiality, integrity, and availability.
Microsoft's Security Response Center advisory at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-21399 details patching guidance. Vicarius provides a detection script at https://www.vicarius.io/vsociety/posts/elevation-of-privilege-vulnerability-in-microsoft-edge-chromium-based-detection-script and a mitigation script at https://www.vicarius.io/vsociety/posts/elevation-of-privilege-vulnerability-in-microsoft-edge-chromium-based-mitigation-script.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2025-2459
Vulnerability Data
Microsoft Edge (Chromium-based) Update Elevation of Privilege Vulnerability
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Secure baseline settings can enforce absolute, organization-controlled paths for critical resources.
Least-functionality configuration can prohibit unapproved directories or executables from being reachable via search paths.
Engineering principles such as trusted paths, complete mediation, and least privilege directly require hard-coded or validated search paths instead of external ones.
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.
Preventing execution of unauthorized code directly blocks the malicious binaries that an untrusted search path would load.
Secure development practices include avoiding or sanitizing externally influenced search paths in application code.
Hardened configuration baselines can enforce safe search paths and restrict environment variables that enable the weakness.
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 discover search-path issues but does not itself prevent them in production code.
Restricting software installation reduces the chance that untrusted binaries or libraries are placed in search paths.
Secure architecture principles include hard-coded or validated search paths and avoiding reliance on untrusted directories.
Secure coding standards require absolute paths or integrity-checked search paths, directly mitigating CWE-426.