SOC status:Duty analyst on shift

UK Cyber Defence
VulnerabilityAnalyzed

CVE-2026-21249

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

LOW 3.3EPSS 11.4%

Does this matter?

EPSS puts the probability of exploitation in the next 30 days at 11.4%, higher than 96% of all known CVEs. Patch or mitigate before the next change window.

Description

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

CVSS 3.1
3.3 LOWCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N
EPSS
11.44% probability · 96th percentile
Public exploits
None in Exploit-DB
CISA KEV
Not listed
Weakness
CWE-73
Affected
microsoft/windows 10 1607 · microsoft/windows 10 1809 · microsoft/windows 10 21h2 · microsoft/windows 10 22h2 · microsoft/windows 11 23h2 · microsoft/windows 11 24h2 · microsoft/windows 11 25h2 · microsoft/windows server 2012 · 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
EPSS trend
0%8%15%26 October 2026: 11.44%26 October 202626 October 2026

EPSS 11.4% since 26 October 2026; no change recorded yet. The dashed line is the ten per cent mark our analysts treat as “patch before the next change window”. Points are recorded when the score first appears and whenever it moves by a percentage point or more.

Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.