CVE-2025-21377 [Medium] | Spoofing in Windows 10 1507

CVE-2025-21377 is rated High Risk (65.1/100): CVSS Medium severity, with high exploitation likelihood (EPSS 21.80%, 97th percentile). EPSS ranks this CVE among the most likely to be exploited in the near term. EPSS rose +17.43% over the last day, indicating growing attacker interest. High exploitation likelihood—assess exposure and prioritize remediation.

#	Date	Old EPSS score	New EPSS score	Delta (New - Old)
1	2026-06-15	4.38%	21.80%	+17.43%
2	2026-05-15	3.80%	4.38%	+0.58%
3	2026-03-26	—	3.80%	—

Date

Old EPSS score

New EPSS score

Delta (New - Old)

2026-06-15

4.38%

21.80%

+17.43%

2026-05-15

3.80%

4.38%

+0.58%

2026-03-26

—

3.80%

—

Base score	Version	Severity	Vector	Exploitability	Impact	Score source
6.5	3.1	MEDIUM	`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N` Click to expand Attack vector (AV:N) Could be attacked over the internet or any normal routed network—not just someone sitting at the machine. Attack complexity (AC:L) Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup. Privileges required (PR:N) No account or special rights needed—anonymous or random user is enough. User interaction (UI:R) A real person has to do something—click, install, enable—otherwise it doesn’t land. Scope (S:U) Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems. Confidentiality (C:H) Serious risk that confidential data gets exposed in a big way. Integrity (I:N) Data isn’t meaningfully altered or forged. Availability (A:N) Service keeps running; no real outage angle.	2.8	3.6	[email protected]

Base score

Version

Severity

Vector

Exploitability

Impact

Score source

6.5

3.1

MEDIUM

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

Attack vector (AV:N): Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L): Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N): No account or special rights needed—anonymous or random user is enough.
User interaction (UI:R): A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:U): Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H): Serious risk that confidential data gets exposed in a big way.
Integrity (I:N): Data isn’t meaningfully altered or forged.
Availability (A:N): Service keeps running; no real outage angle.

2.8

3.6

[email protected]

Affected software / configurations for CVE-2025-21377

Vendor	Product	Version	Raw CPE
microsoft	windows_10_1507	< 10.0.10240.20915	cpe:2.3:o:microsoft:windows_10_1507:::::::x64:*
microsoft	windows_10_1507	< 10.0.10240.20915	cpe:2.3:o:microsoft:windows_10_1507:::::::x86:*
microsoft	windows_10_1607	< 10.0.14393.7785	cpe:2.3:o:microsoft:windows_10_1607:::::::x64:*
microsoft	windows_10_1607	< 10.0.14393.7785	cpe:2.3:o:microsoft:windows_10_1607:::::::x86:*
microsoft	windows_10_1809	< 10.0.17763.6893	cpe:2.3:o:microsoft:windows_10_1809:::::::x64:*
microsoft	windows_10_1809	< 10.0.17763.6893	cpe:2.3:o:microsoft:windows_10_1809:::::::x86:*
microsoft	windows_10_21h2	< 10.0.19044.5487	cpe:2.3:o:microsoft:windows_10_21h2::::::::
microsoft	windows_10_22h2	< 10.0.19045.5487	cpe:2.3:o:microsoft:windows_10_22h2::::::::
microsoft	windows_11_22h2	< 10.0.22621.4890	cpe:2.3:o:microsoft:windows_11_22h2::::::::
microsoft	windows_11_23h2	<= 10.0.22631.4890	cpe:2.3:o:microsoft:windows_11_23h2::::::::
microsoft	windows_11_24h2	< 10.0.26100.3194	cpe:2.3:o:microsoft:windows_11_24h2::::::::
microsoft	windows_server_2008	—	cpe:2.3:o:microsoft:windows_server_2008:-:sp2:::::x64:*
microsoft	windows_server_2008	—	cpe:2.3:o:microsoft:windows_server_2008:-:sp2:::::x86:*
microsoft	windows_server_2008	r2	cpe:2.3:o:microsoft:windows_server_2008:r2:sp1:::::x64:*
microsoft	windows_server_2012	—	cpe:2.3:o:microsoft:windows_server_2012:-:::::::*
microsoft	windows_server_2012	r2	cpe:2.3:o:microsoft:windows_server_2012:r2:::::::*
microsoft	windows_server_2016	< 10.0.14393.7785	cpe:2.3:o:microsoft:windows_server_2016::::::::
microsoft	windows_server_2019	< 10.0.17763.6893	cpe:2.3:o:microsoft:windows_server_2019::::::::
microsoft	windows_server_2022	< 10.0.20348.3207	cpe:2.3:o:microsoft:windows_server_2022::::::::
microsoft	windows_server_2022_23h2	< 10.0.25398.1425	cpe:2.3:o:microsoft:windows_server_2022_23h2:::::::x64:*
microsoft	windows_server_2025	< 10.0.26100.3194	cpe:2.3:o:microsoft:windows_server_2025:::::::x64:*

References for CVE-2025-21377

URL	Tags
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-21377	Patch Vendor Advisory

URL

CVE-2025-21377 | NTLM Hash Disclosure Spoofing Vulnerability

Exploit prediction scoring system (EPSS) score for CVE-2025-21377

Common vulnerability scoring system (CVSS) metrics for CVE-2025-21377

Weakness enumeration for CVE-2025-21377

Affected software / configurations for CVE-2025-21377

References for CVE-2025-21377