CVE-2025-21266
Published: 14 January 2025
Summary
CVE-2025-21266 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 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 SI-2 (Flaw Remediation) and CM-7 (Least Functionality).
Deeper analysis
CVE-2025-21266 is a remote code execution vulnerability in the Windows Telephony Service, carrying a CVSS 3.1 base score of 8.8. The flaw is associated with CWE-122 and permits an attacker to execute arbitrary code on an affected Windows system when certain conditions are met.
An unauthenticated remote attacker can trigger the issue over the network with low attack complexity. Successful exploitation requires user interaction but results in full compromise of confidentiality, integrity, and availability on the target system without any change in scope.
Microsoft has published mitigation guidance and patch information for the vulnerability in its Security Response Center advisory at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-21266. The current EPSS score of 0.0225 shows no material increase from its recorded peak, indicating limited observed exploitation interest to date.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2025-2331
Vulnerability details
Windows Telephony Service Remote Code Execution Vulnerability
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
RCE vulnerability in Windows service with network vector and explicit user interaction requirement (e.g., malicious link/file) directly enables client-side exploitation for arbitrary code execution.
CVEs Like This One
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Directly remediates the Windows Telephony Service RCE vulnerability (CVE-2025-21266) by applying vendor patches as specified in the MSRC advisory.
Implements memory protections like ASLR and DEP to mitigate stack-based buffer overflow (CWE-122) exploitation leading to RCE in the service.
Restricts the system to least functionality by disabling the non-essential Windows Telephony Service, removing the vulnerable attack surface.