CVE-2025-21303
Published: 14 January 2025
Summary
CVE-2025-21303 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 for Client Execution (T1203); ranked in the top 17.5% 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 SI-16 (Memory Protection) and SI-2 (Flaw Remediation).
Deeper analysis
Windows Telephony Service contains a remote code execution vulnerability tracked as CVE-2025-21303. The flaw is present in the Windows Telephony Service component and carries a CVSS 3.1 base score of 8.8, reflecting network attack vector, low attack complexity, no required privileges, and required user interaction, with high impact on confidentiality, integrity, and availability. The associated weakness identifiers are CWE-122 and NVD-CWE-noinfo.
An unauthenticated remote attacker can exploit the issue over the network by convincing a user to perform an action that triggers the vulnerable code path, resulting in arbitrary code execution with the privileges of the Telephony Service. Successful exploitation would allow the attacker to run malicious code, install programs, view or modify data, or create new accounts on the affected system.
Microsoft has published an advisory for CVE-2025-21303 that includes mitigation guidance and patch availability. The EPSS score remains flat at 0.0167 with no material increase since disclosure, indicating limited observed exploitation interest to date.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2025-2368
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 Windows Telephony Service requiring user interaction with a malicious file or network resource, directly mapping to exploitation of a client application vulnerability for code execution.
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Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Directly addresses the vulnerability by requiring timely remediation through application of vendor patches for the heap-based buffer overflow in Windows Telephony Service.
Implements memory protections like ASLR and DEP that significantly hinder exploitation of heap-based buffer overflows leading to remote code execution.
Requires input validation to mitigate buffer overflows in services processing untrusted network resources or files handled by Windows Telephony Service.