CVE-2025-21339 [High] | RCE in Windows 10 1507

CVE-2025-21339 is rated High Risk (69.5/100): CVSS High severity, with high exploitation likelihood (EPSS 8.06%, 92th percentile). EPSS ranks this CVE among the most likely to be exploited in the near term. EPSS rose +1.96% 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	2026-06-05	6.10%	8.06%	+1.96%
2	2026-03-17	5.49%	6.10%	+0.61%
3	2026-02-22	—	5.49%	—

Date

Old EPSS score

New EPSS score

Delta (New - Old)

2026-06-05

6.10%

8.06%

+1.96%

2026-03-17

5.49%

6.10%

+0.61%

2026-02-22

—

5.49%

—

Base score	Version	Severity	Vector	Exploitability	Impact	Score source
8.8	3.1	HIGH	`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H` 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:H) They could widely tamper with or forge data—trust in the data is badly hurt. Availability (A:H) Could take the service down hard or make it unusable for people who depend on it.	2.8	5.9	[email protected]

Base score

Version

Severity

Vector

Exploitability

Impact

Score source

8.8

3.1

HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H 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:H): They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H): Could take the service down hard or make it unusable for people who depend on it.

2.8

5.9

[email protected]

Affected software / configurations for CVE-2025-21339

Vendor	Product	Version	Raw CPE
microsoft	windows_10_1507	< 10.0.10240.20890	cpe:2.3:o:microsoft:windows_10_1507:::::::x64:*
microsoft	windows_10_1507	< 10.0.10240.20890	cpe:2.3:o:microsoft:windows_10_1507:::::::x86:*
microsoft	windows_10_1607	< 10.0.14393.7699	cpe:2.3:o:microsoft:windows_10_1607:::::::x64:*
microsoft	windows_10_1607	< 10.0.14393.7699	cpe:2.3:o:microsoft:windows_10_1607:::::::x86:*
microsoft	windows_10_1809	< 10.0.17763.6775	cpe:2.3:o:microsoft:windows_10_1809:::::::x64:*
microsoft	windows_10_1809	< 10.0.17763.6775	cpe:2.3:o:microsoft:windows_10_1809:::::::x86:*
microsoft	windows_10_21h2	< 10.0.19044.5371	cpe:2.3:o:microsoft:windows_10_21h2::::::::
microsoft	windows_10_22h2	< 10.0.19045.5371	cpe:2.3:o:microsoft:windows_10_22h2::::::::
microsoft	windows_11_22h2	< 10.0.22621.4751	cpe:2.3:o:microsoft:windows_11_22h2::::::::
microsoft	windows_11_23h2	< 10.0.22631.4751	cpe:2.3:o:microsoft:windows_11_23h2::::::::
microsoft	windows_11_24h2	< 10.0.26100.2894	cpe:2.3:o:microsoft:windows_11_24h2::::::::
microsoft	windows_server_2008	—	cpe:2.3:o:microsoft:windows_server_2008:-:sp2::::::
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	< 10.0.14393.7699	cpe:2.3:o:microsoft:windows_server_2016::::::::
microsoft	windows_server_2019	< 10.0.17763.6775	cpe:2.3:o:microsoft:windows_server_2019::::::::
microsoft	windows_server_2022	< 10.0.20348.3091	cpe:2.3:o:microsoft:windows_server_2022::::::::
microsoft	windows_server_2022_23h2	< 10.0.25398.1369	cpe:2.3:o:microsoft:windows_server_2022_23h2::::::::
microsoft	windows_server_2025	< 10.0.26100.2894	cpe:2.3:o:microsoft:windows_server_2025:::::::x64:*

References for CVE-2025-21339

URL	Tags
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-21339	Patch Vendor Advisory

URL

CVE-2025-21339 | Windows Telephony Service Remote Code Execution Vulnerability

Exploit prediction scoring system (EPSS) score for CVE-2025-21339

Common vulnerability scoring system (CVSS) metrics for CVE-2025-21339

Weakness enumeration for CVE-2025-21339

Affected software / configurations for CVE-2025-21339

References for CVE-2025-21339