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Low severity · published Feb 10, 2026
CVE-2026-21249
Windows NTLM Spoofing Vulnerability
3.3
CVSS
11.4%
EPSS
No
On KEV
Description
External control of file name or path in Windows NTLM allows an unauthorized attacker to perform spoofing locally.
CVSS vector
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N
Attack vector
Local
Complexity
Low
Privileges
None
User interaction
Required
Confidentiality
Low
Integrity
None
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)11.4% · higher than 96% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
W1
Windows 10 Version 1607 · Microsoft
10.0.14393.0 before 10.0.14393.8868 · source: vendor
W1
Windows 10 Version 1809 · Microsoft
10.0.17763.0 before 10.0.17763.8389 · source: vendor
W1
Windows 10 Version 21H2 · Microsoft
10.0.19044.0 before 10.0.19044.6937 · source: vendor
W1
Windows 10 Version 22H2 · Microsoft
10.0.19045.0 before 10.0.19045.6937 · source: vendor
W1
Windows 11 Version 23H2 · Microsoft
10.0.22631.0 before 10.0.22631.6649 · source: vendor
W1
Windows 11 Version 24H2 · Microsoft
10.0.26100.0 before 10.0.26100.7840 · source: vendor
W1
Windows 11 Version 25H2 · Microsoft
10.0.26200.0 before 10.0.26200.7840 · source: vendor
W1
Windows 11 version 22H3 · Microsoft
10.0.22631.0 before 10.0.22631.6649 · source: vendor
W1
Windows 11 version 26H1 · Microsoft
10.0.28000.0 before 10.0.28000.1575; 10.0.28000.0 before 10.0.28000.1575 · source: vendor
WS
Windows Server 2012 R2 · Microsoft
6.3.9600.0 before 6.3.9600.23022 · source: vendor
WS
Windows Server 2012 R2 (Server Core installation) · Microsoft
6.3.9600.0 before 6.3.9600.23022 · source: vendor
WS
Windows Server 2016 · Microsoft
10.0.14393.0 before 10.0.14393.8868 · source: vendor, NVD
Affected product
W1
Windows 10 Version 1607
Microsoft
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-21249
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-21249
Vendor Advisory
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21249
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