How severe is CVE-2025-21406?

CVE-2025-21406 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2025-21406 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (76th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2025-21406?

CVE-2025-21406 primarily affects Microsoft Windows 10 1507. In total, 21 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2025-21406?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

Does CVE-2025-21406 have an EU (EUVD) identifier?

Yes. CVE-2025-21406 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-2466.

When was CVE-2025-21406 published?

CVE-2025-21406 was published on 2025-02-11 and last updated on 2026-06-17.

CVE-2025-21406

CVE-2025-21406 is a high-severity vulnerability in Microsoft Windows 10 1507 with a CVSS 3.x base score of 8.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-416.

Key facts

Severity: High (CVSS 3.x base score 8.8)
EPSS exploit prediction: 2% (76th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2025-2466
Weakness: CWE-416
Affected product: Microsoft Windows 10 1507
Published: 2025-02-11
Last modified: 2026-06-17

Description

Windows Telephony Service Remote Code Execution Vulnerability

Frequently asked questions

What is CVE-2025-21406?: Windows Telephony Service Remote Code Execution Vulnerability
How severe is CVE-2025-21406?: CVE-2025-21406 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2025-21406 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (76th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2025-21406?: CVE-2025-21406 primarily affects Microsoft Windows 10 1507. In total, 21 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2025-21406?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2025-21406 have an EU (EUVD) identifier?: Yes. CVE-2025-21406 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-2466.
When was CVE-2025-21406 published?: CVE-2025-21406 was published on 2025-02-11 and last updated on 2026-06-17.

References

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-21406

Affected products (21)

cpe:2.3:o:microsoft:windows_10_1507:*:*:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_10_1507:*:*:*:*:*:*:x86:*
cpe:2.3:o:microsoft:windows_10_1607:*:*:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_10_1607:*:*:*:*:*:*:x86:*
cpe:2.3:o:microsoft:windows_10_1809:*:*:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_10_1809:*:*:*:*:*:*:x86:*
cpe:2.3:o:microsoft:windows_10_21h2:*:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_10_22h2:*:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_11_22h2:*:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_11_23h2:*:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_11_24h2:*:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2008:-:sp2:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_server_2008:-:sp2:*:*:*:*:x86:*
cpe:2.3:o:microsoft:windows_server_2008:r2:sp1:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_server_2012:-:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2012:r2:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2016:*:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2019:*:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2022:*:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2022_23h2:*:*:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_server_2025:*:*:*:*:*:*:x64:*

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