SOC status:Duty analyst on shift

UK Cyber Defence
VulnerabilityAnalyzed

CVE-2025-21391

Microsoft Windows Storage Link Following Vulnerability

KEVHIGH 7.1EPSS 2.30%

Does this matter?

Known to be exploited in the wild (CISA KEV, CISA remediation deadline 4 March 2025). Treat as an emergency change: patch or isolate now, then hunt for prior compromise.

Description

Windows Storage Elevation of Privilege Vulnerability

CVSS 3.1
7.1 HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H
EPSS
2.30% probability · 82th percentile
CISA KEV
Listed 11 February 2025 · due 4 March 2025
Weakness
CWE-59
Affected
microsoft/windows 10 1507 · microsoft/windows 10 1607 · 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
Source
secure@microsoft.com

CISA notes

Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable. https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-21391 ; https://nvd.nist.gov/vuln/detail/CVE-2025-21391

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.