What is CVE-2025-21371?

CVE-2025-21371 is a high-severity software vulnerability (CWE-122) with a CVSS score of 8.8. Windows Telephony Service Remote Code Execution Vulnerability

Is CVE-2025-21371 being actively exploited?

It is not currently in CISA's KEV catalog. Its EPSS exploitation probability is 2%.

What products does CVE-2025-21371 affect?

Tracked products affected include Windows Server 2022. Check the version you run to see whether it is affected.

How do I fix CVE-2025-21371?

Apply the vendor fix promptly. An official patch or advisory is available. Upgrade affected products to a fixed version.

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CVE-2025-21371

HIGH severity · CVSS 8.8 · CWE-122

8.8CVSS HIGH

Summary

Windows Telephony Service Remote Code Execution Vulnerability

Impact & exploitability

Attack vectorNetwork

Attack complexityLow

Privileges requiredNone

User interactionRequired

Confidentiality impactHigh

Integrity impactHigh

Availability impactHigh

Exploit probability (EPSS)2%

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

Affected products we track (1)

Windows Server 2022

Recommendation

Apply the vendor fix promptly. Open any affected product above for its exact safe version.

Official patch: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-21371 ↗

Additional information

NVD record
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-21371Patch
https://www.vicarius.io/vsociety/posts/windows-telephony-service-remote-code-execution-vulnerability-detection-script
https://www.vicarius.io/vsociety/posts/windows-telephony-service-remote-code-execution-vulnerability-mitigation-script