CVE-2026-21249

Windows NTLM Spoofing Vulnerability

Exploitation likely. EPSS gives it a 11% chance of exploitation in the next 30 days. A vendor fix is available.

Published 2026-02-10Updated 2026-02-11Sources: CVE.org, NVD, BDU

What to do

The vendor has published a fix. Version details are below where the sources state them.

External control of file name or path in Windows NTLM allows an unauthorized attacker to perform spoofing locally.

No plain-language summary for this CVE yet.

Where each signal puts this CVE on the scale from published to confirmed exploited.

EPSS96th

CISA KEV

Not in the catalog. CISA has not confirmed exploitation.

Public exploits

No public exploit or proof of concept found in the sources we track.

EPSS

11% chance of exploitation activity in the next 30 days, which ranks it in the 96th percentile of scored CVEs.

Exploit Prediction Scoring System, FIRST.org. A probability, not a confirmation.

6 events over 135 days, from the signal feeds we watch.

And 44 more affected products. See all after sign-in

CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N

Scored 3.3 by NVD.

Attack Vector LocalRequires local access to the vulnerable system (e.g. local login, malicious file)
Attack Complexity LowNo special conditions — the attack can be reliably reproduced
Privileges Required NoneNo authentication required — anyone can exploit this
User Interaction RequiredA user must click a link, open a file, or perform some action

Confidentiality LowSome restricted information is disclosed, but limited in scope
Integrity NoneNo integrity impact
Availability NoneNo availability impact