Zero-day vulnerability in Windows

Link following
CVE-2025-21391

Vulnerability details

Advisory: SB2025021190 - Arbitrary file deletion in Windows Storage

Vulnerable component: Windows

CVE-ID: CVE-2025-21391

CVSSv3 score: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N/E:H/RL:O/RC:C

CWE-ID: CWE-59 - Improper Link Resolution Before File Access ('Link Following')

Description:

The vulnerability allows a local user to delete files on the system.

The vulnerability exists due to insecure link following in Windows Storage. A local user can delete arbitrary files on the system.

Note, the vulnerability is being actively exploited in the wild.

External links:

https://msrc.microsoft.com/update-guide/en-US/advisory/CVE-2025-21391

About zero-day vulnerabilities

Zero-day vulnerability is an undisclosed vulnerability in software that hackers can exploit to compromise computer programs, gain unauthorized access to sensitive data, penetrate networks, etc. We consider vulnerability a zero-day when there is no solution provided from software vendor and the vulnerability is being actively exploited by malicious actors.

Zero-day candidate is a potential zero-day vulnerability in software which might have been used in targeted attacks, however there is no evidence to support this suggestion.