CVE-2025-21306
Published: 14 January 2025
Summary
CVE-2025-21306 is a high-severity Heap-based Buffer Overflow (CWE-122) vulnerability in Microsoft Windows 10 1507. Its CVSS base score is 8.8 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation of Remote Services (T1210); ranked in the top 15.0% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified are NIST 800-53 CM-7 (Least Functionality) and SI-2 (Flaw Remediation).
Deeper analysis
CVE-2025-21306 is a remote code execution vulnerability in the Windows Telephony Service. It carries a CVSS 3.1 base score of 8.8 and is associated with CWE-122. The flaw affects the Telephony Service component on Windows systems and was published on 14 January 2025.
An unauthenticated remote attacker can exploit the issue over the network with low attack complexity and no privileges, provided the victim performs a single user interaction. Successful exploitation grants the attacker full confidentiality, integrity, and availability impact on the affected system.
Microsoft has published an advisory describing the vulnerability and associated patches at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-21306. The current EPSS score of 0.0225 has shown no material increase since disclosure.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2025-2371
Vulnerability details
Windows Telephony Service Remote Code Execution Vulnerability
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
The CVE describes a remote code execution vulnerability in the Windows Telephony Service exploitable by an unauthenticated network attacker, directly mapping to exploitation of remote services for code execution on the target system.
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Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Directly mitigates CVE-2025-21306 by requiring timely patching of the Windows Telephony Service vulnerability as detailed in Microsoft's update guide.
Prevents exploitation by configuring systems to disable or restrict the unnecessary Windows Telephony Service, reducing the attack surface for this RCE vulnerability.
Identifies systems vulnerable to CVE-2025-21306 through vulnerability scanning, enabling prioritization of remediation efforts.