CVE-2026-21249Disclosure(microsoft / windows_10_1607)

LOWCVSS 3.3 · LOW

Signal is active with 1 mentions in latest observed window

Immediate actions

Track advisory updates for patch or workaround availability

Recommended action window: Monitor and triage in normal cycle

NVD description

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

microsoft CVEs Back to dashboard

0.5/ 10 priority

Sources & remediation

Vendor / third-party advisories

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21249

Weakness type (CWE)

CWE-73

Priority

LOW

Exploitation

NONE

PoC

NONE

Patch

NONE

Momentum

NONE

Are you affected?

If you run products in this scope, you should treat this CVE as relevant to your environment.

windows_10_1607
windows_10_1809
windows_10_21h2
windows_10_22h2

Threat summary

1 mentions across 1 observed day

What's happening

Technical details provided in 1 signal
Disclosure: 1 classified signal
1 total mentions across 1 day

Affected systems

Vendors

microsoft

Products

windows_10_1607windows_10_1809windows_10_21h2windows_10_22h2windows_11_23h2windows_11_24h2windows_11_25h2windows_server_2012windows_server_2016windows_server_2019

1 version affected across 13 products

Deep dive

Activity timeline1 mentions / 1d

Signal classification1 categories

Disclosure

1100.0%

Referenced assets1 URL

By indicator

https://www.cve.org/CVERecord?id=CVE-2026-21249

Full discourse1 post

CVE@CVEnew240d
Disclosure
CVE-2026-21249 External control of file name or path in Windows NTLM allows an unauthorized attacker to perform spoofing locally. https://www.cve.org/CVERecord?id=CVE-2026-21249
Post summary
The brief statement announces CVE-2026-21249, describing a Windows NTLM flaw that permits local spoofing through externally controlled file names or paths.
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56.5K followersView on X

CPE platform detail22 entries

Part:

Vendor:

Product:

Version:

Target SW:

Target HW:

22 of 22 entries

Part	Vendor	Product	Version	Target SW	Target HW
OS	microsoft	windows_10_1607	-	-	x64
OS	microsoft	windows_10_1607	-	-	x86
OS	microsoft	windows_10_1809	-	-	x64
OS	microsoft	windows_10_1809	-	-	x86
OS	microsoft	windows_10_21h2	-	-	arm64
OS	microsoft	windows_10_21h2	-	-	x64
OS	microsoft	windows_10_21h2	-	-	x86
OS	microsoft	windows_10_22h2	-	-	arm64
OS	microsoft	windows_10_22h2	-	-	x64
OS	microsoft	windows_10_22h2	-	-	x86
OS	microsoft	windows_11_23h2	-	-	arm64
OS	microsoft	windows_11_23h2	-	-	x64
OS	microsoft	windows_11_24h2	-	-	arm64
OS	microsoft	windows_11_24h2	-	-	x64
OS	microsoft	windows_11_25h2	-	-	arm64
OS	microsoft	windows_11_25h2	-	-	x64
OS	microsoft	windows_server_2012	r2	-	-
OS	microsoft	windows_server_2016	-	-	-
OS	microsoft	windows_server_2019	-	-	-
OS	microsoft	windows_server_2022	-	-	-
OS	microsoft	windows_server_2022_23h2	-	-	-
OS	microsoft	windows_server_2025	-	-	-

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