Raw vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:HSummary
CVE-2026-25667 is a high-severity Uncontrolled Resource Consumption (CWE-400) vulnerability in Microsoft .Net. Its CVSS base score is 7.5 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique OS Exhaustion Flood (T1499.001); ranked in the top 14% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.
The strongest mitigations our analysis identified map to SC-5 (Denial-of-service Protection) and SC-6 (Resource Availability) — see the control section below for these in your framework.
Deeper analysis AI-assisted summary
Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.
ASP.NET Core Kestrel, the web server component in Microsoft .NET 8.0 prior to 8.0.22 and .NET 9.0 prior to 9.0.11, contains a denial-of-service vulnerability (CVE-2026-25667) that stems from an incorrect exit condition during HTTP/3 Encoder/Decoder stream processing over QUIC. The flaw is tracked under CWE-400 and carries a CVSS 3.1 score of 7.5, reflecting network-reachable, unauthenticated input that produces high availability impact without affecting confidentiality or integrity.
An unauthenticated remote attacker can trigger excessive CPU consumption simply by transmitting a single crafted QUIC packet, thereby degrading or halting service for the affected Kestrel instance. No user interaction or special privileges are required, and the attack surface is exposed whenever HTTP/3 is enabled.
Public references include a patch commit in the aspnetcore repository that corrects the stream-processing exit logic, along with proof-of-concept and fuzzing tools that demonstrate the packet construction. The associated EPSS score rose from a low baseline to a peak of 0.1450 on 2026-04-30 before receding to 0.0660, indicating measurable post-disclosure exploitation interest that warrants renewed attention even after the initial disclosure window.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-13148
Vulnerability Data
ASP.NET Core Kestrel in Microsoft .NET 8.0 before 8.0.22 and .NET 9.0 before 9.0.11 allows a remote attacker to cause excessive CPU consumption by sending a crafted QUIC packet, because of an incorrect exit condition for HTTP/3 Encoder/Decoder stream processing.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
SC-5 directly limits the effects of resource-exhaustion events that constitute uncontrolled consumption.
SC-6 enforces explicit allocation limits on resources, structurally preventing the weakness from occurring.
Process isolation confines resource consumption to separate domains, reducing blast radius without stopping the root flaw.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Explicitly requires monitoring and maintaining resource capacity, directly addressing uncontrolled consumption to preserve availability.
Continuous monitoring of computing resources can detect resource exhaustion but does not itself enforce allocation limits.
Resilience mechanisms such as avoiding single points of failure indirectly reduce impact of resource exhaustion.
Hardened configuration baselines can include resource quotas and limits that constrain consumption.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
Resource-utilization monitoring and alerting on bottlenecks or overloads limits the impact of denial-of-service or resource-exhaustion attacks.
By continuously monitoring utilization, stress-testing peak loads, and maintaining documented plans to scale or throttle resources, the control directly limits an attacker’s ability to drive a system into uncontrolled resource exhaustion.
Pre-agreed severity-based prioritization and resource allocation during incident triage reduce the likelihood that an attacker-induced resource exhaustion will overwhelm the organization before corrective action is taken.
Business-continuity plans that include resource-management controls reduce the likelihood that an attacker can trigger uncontrolled resource consumption by forcing the system into a degraded or fallback state.
Defining RTOs and capacity requirements for ICT services during business-impact analysis forces organizations to provision sufficient resources and throttling mechanisms, reducing the likelihood that an attacker can induce denial-of-service through uncontrolled resource consumption.
Early notification of anomalous resource consumption or system malfunctions enables throttling or isolation before availability is lost.