Is CVE-2025-21391 being actively exploited?

Yes. CVE-2025-21391 is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, added on February 11, 2025.

What is the CVSS score for CVE-2025-21391?

CVE-2025-21391 has a CVSS 3.1 base score of 7.1 (HIGH).

CVE-2025-21391

HIGH · CVSS 7.1CISA KEV: actively exploitedEPSS 2.3%EU EUVD: exploited

Windows Storage Elevation of Privilege Vulnerability

Key facts

CVSS score: 7.1 (v3.1)
Severity: HIGH
CVSS vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H
Weakness (CWE): CWE-59
EPSS score: 2.3% (83th percentile)
In CISA KEV: Yes, added February 11, 2025
In EU EUVD: Yes (EUVD-2025-2452)
Published: February 11, 2025
NVD last modified: September 24, 2026
Status: Analyzed

CISA Known Exploited Vulnerability

Microsoft Windows Storage Link Following Vulnerability

Added to the KEV catalog on February 11, 2025; federal remediation due March 4, 2025.

EU Vulnerability Database (EUVD)

This vulnerability is also tracked by ENISA as EUVD-2025-2452 in the EU Vulnerability Database. ENISA flags it as known exploited. Last updated in EUVD on February 26, 2026.

View on the EU Vulnerability Database

Affected products

microsoft / windows 10 1507
microsoft / windows 10 1507
microsoft / windows 10 1607
microsoft / windows 10 1607
microsoft / windows 10 1809
microsoft / windows 10 1809
microsoft / windows 10 21h2
microsoft / windows 10 22h2
microsoft / windows 11 22h2
microsoft / windows 11 23h2
microsoft / windows 11 24h2
microsoft / windows server 2016
microsoft / windows server 2019
microsoft / windows server 2022
microsoft / windows server 2022 23h2
microsoft / windows server 2025

Certified products that may be affected

1 FIPS 140 or Common Criteria certified product, from automated matching by sec-certs.org.

Microsoft Windows 10 and Server version 1903 (May 2019 Update) - Microsoft Corporation - Common Criteria 2019-22-INF-2839 - archived

References

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-21391(Patch, Vendor Advisory)
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-21391(US Government Resource)

Last updated September 26, 2026 · Source: NVD, CISA KEV, FIRST.org EPSS

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