CVE-2025-21276
Published: 14 January 2025
Summary
CVE-2025-21276 is a high-severity Wrap or Wraparound (CWE-191) vulnerability in Microsoft Windows 10 1507. Its CVSS base score is 7.5 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Application or System Exploitation (T1499.004); ranked in the top 8.5% 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 SC-5 (Denial-of-service Protection) and SI-2 (Flaw Remediation).
Deeper analysis
CVE-2025-21276 is a denial-of-service vulnerability in the Windows MapUrlToZone component. It carries a CVSS 3.1 base score of 7.5 with a network attack vector, low attack complexity, and no required privileges or user interaction, resulting in high impact to availability while leaving confidentiality and integrity unaffected. The weakness is tracked under CWE-191 and CWE-693.
An unauthenticated attacker can send specially crafted input over the network to trigger the flaw and cause the affected Windows component to stop responding, producing a denial-of-service condition. Because the attack requires no authentication or user assistance, it can be launched remotely by any party with network reachability to the target system.
Microsoft’s Security Response Center advisory at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-21276 describes the available security updates that address the issue. The associated EPSS score rose from a low baseline to a peak of 0.1544 on 2026-02-13 before receding to its current value of 0.0678, indicating a period of increased exploitation interest after disclosure.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2025-2341
Vulnerability details
Windows MapUrlToZone Denial of Service Vulnerability
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Remote unauthenticated exploitation of the MapUrlToZone component directly enables endpoint DoS via application/system exploitation (T1499.004).
CVEs Like This One
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Flaw remediation directly prevents exploitation of CVE-2025-21276 by applying Microsoft patches to the vulnerable MapUrlToZone component.
Denial-of-service protection mechanisms such as rate limiting and resource controls mitigate remote unauthenticated attacks causing availability impact via MapUrlToZone.
Information input validation restricts malformed URL inputs that trigger the DoS condition in the MapUrlToZone component.