CVE-2025-27473
Published: 08 April 2025
Summary
CVE-2025-27473 is a high-severity Uncontrolled Resource Consumption (CWE-400) vulnerability in Microsoft Windows Server 2008. Its CVSS base score is 7.5 (High).
Operationally, ranked in the top 3.3% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.
Deeper analysis
CVE-2025-27473 is an uncontrolled resource consumption vulnerability, tracked under CWE-400, that affects the HTTP.sys kernel-mode driver in Windows. The flaw permits remote attackers to trigger excessive resource use through specially crafted network traffic, resulting in denial of service without any authentication or user interaction required.
An unauthenticated attacker with network access can exploit the issue over the internet or internal networks to exhaust resources in HTTP.sys, rendering affected systems unresponsive. The vulnerability carries a CVSS v3.1 score of 7.5, reflecting its high availability impact combined with low attack complexity and no prerequisites.
Microsoft's advisory at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-27473 addresses the flaw and is the authoritative source for mitigation steps, including available patches.
The EPSS score for this CVE reached a peak of 0.4442 after disclosure before settling at a current value of 0.2927, indicating a material rise in exploitation interest that warrants renewed attention from defenders.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2025-10170
Vulnerability details
Uncontrolled resource consumption in Windows HTTP.sys allows an unauthorized attacker to deny service over a network.
- CWE(s)
Related Threats
No named actor attribution yet. ATT&CK technique mapping in progress for this CVE.
Affected Assets
Mitigating Controls
Likely Mitigating Controls AI
Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.
Limiting concurrent sessions directly prevents uncontrolled resource consumption by capping the number of active sessions per user or account.
Analysis identifies uncontrolled resource consumption indicative of denial-of-service or abuse attempts.
Contingency plan testing includes resource exhaustion scenarios to verify recovery, making it harder for attackers to sustain exploits that cause uncontrolled consumption.
Updated contingency plans include current procedures to detect, contain, and recover from resource exhaustion, limiting an attacker's ability to sustain impact from uncontrolled consumption.
Alternate site allows resumption of operations if resource exhaustion at the primary site is exploited to cause unavailability.
Alternate telecommunications services enable resumption of essential functions when primary services become unavailable due to uncontrolled resource consumption.
The team can analyze and respond to resource exhaustion incidents, reducing the impact of attacks that exploit uncontrolled consumption weaknesses.
Timely maintenance support and spare parts enable rapid recovery from failures induced by uncontrolled resource consumption, shortening the impact window of denial-of-service attacks.