CVE-2025-21307
Published: 14 January 2025
Summary
CVE-2025-21307 is a critical-severity Use After Free (CWE-416) vulnerability in Microsoft Windows 10 1507. Its CVSS base score is 9.8 (Critical).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked in the top 5.5% 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-2 (Flaw Remediation) and CM-7 (Least Functionality).
Deeper analysis
The vulnerability CVE-2025-21307 is a remote code execution flaw in the Windows Reliable Multicast Transport Driver (RMCAST) component, associated with CWE-416 use-after-free weaknesses. It affects Windows systems and is rated 9.8 under CVSS 3.1, reflecting network attack vector, low complexity, and no requirements for privileges or user interaction.
An unauthenticated remote attacker can send specially crafted network traffic to trigger the flaw, resulting in arbitrary code execution that grants full control over confidentiality, integrity, and availability on the target host.
Microsoft has published an advisory for CVE-2025-21307 at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-21307 that practitioners should reference for official mitigation guidance. The associated EPSS score has remained flat at 0.1405 with no material increase observed since disclosure.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2025-2372
Vulnerability details
Windows Reliable Multicast Transport Driver (RMCAST) Remote Code Execution Vulnerability
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Remote unauthenticated RCE in network-exposed Windows driver directly enables exploitation of public-facing applications (T1190) and facilitates arbitrary code execution via command/scripting interpreters like PowerShell (T1059.001).
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Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Directly remediates the use-after-free vulnerability in the Windows RMCAST driver by applying vendor-provided patches, preventing remote code execution.
Limits attack surface by configuring the system to disable the RMCAST driver and other unnecessary multicast transport capabilities when not required.
Monitors and controls network communications at boundaries to block unauthorized inbound multicast traffic that could trigger the RMCAST remote code execution vulnerability.