Threats / Microsoft / CVE-2025-21391
CVE-2025-21391
· EUVD no mirror located
· GCVE no mirror located
Verified 2026-06-22
Microsoft Windows vulnerability
Microsoft Windows Storage contains a link following vulnerability enabling privilege escalation and potential data deletion or service disruption.
Verdict
Today item — known-exploited.
A link following flaw in Windows Storage allows attackers to escalate privileges and delete data, potentially causing service unavailability. Active exploitation observed in the wild.
01
Is it exploitable?
— the evidence, ranked above the scoreReported exploitation
5 independent public reports of in-the-wild exploitation are cataloged.Distinct reporting sources (vendor, incident response, government); open them for the underlying claims.
Exploited in the wild
Listed in the CISA Known Exploited Vulnerabilities catalog (added 2025-02-11).
Probability (EPSS)
EPSS 0.02143 — modeled likelihood of exploitation activity.EPSS is a daily-changing model output — open the source for today's value.
Severity / affected
Affected: Microsoft, Windows. Confirm exact fixed builds in the vendor advisory.
Weakness (CWE)
Mapped to CWE-59 Link Following — weakness family: Path traversal / file.CWE assignment from the public NVD record; the weakness class drives how the flaw is exploited.
02
Who’s exploiting it?
— attribution turns risk into urgencyAttribution not established
No confirmed (advisory-backed) threat-actor attribution is established for this record. Absence of a named actor is not absence of compromise — see Coverage & confidence.
03
Why it matters
— the attack path, told twice: adversary, then board1
Front door — unauthenticated access narrative 1
Attacker
I craft a malicious symbolic link or junction point in a location the Storage service will follow during its operations.
Business
Attacker gains elevated privileges by exploiting the service's trusted execution context.
2
Keys to the kingdom — privilege/identity takeover narrative 2
Attacker
I direct the Storage service to access or modify files outside its intended scope through the link.
Business
Critical data becomes accessible or modifiable by unprivileged actors, compromising data integrity.
3
Lateral reach — past segmentation narrative 3
Attacker
I delete essential storage-related files or configuration data via the escalated access path.
Business
Storage services become unavailable, disrupting dependent systems and business operations.
04
What to do
— defensible action- Remediate per the vendor advisory — confirm the fixed build for your version and verify exposure.1
Say it to the boardA vulnerability with this evidence profile is a defensible budget line, not a backlog ticket — fund the change against the proof above.
05