🚨 CRITICALvulnerabilityNov 7, 2025

HTTP/2 MadeYouReset CVE-2025-8671 - Internet-Scale DoS Risk

Category:Threat Alerts / Vulnerabilities & Exploits

HTTP/2 MadeYouReset CVE-2025-8671 exposes a protocol-level weakness that enables powerful denial-of-service and distributed denial-of-service attacks against websites, APIs, and reverse proxies built on HTTP/2. HTTP/2 MadeYouReset CVE-2025-8671 abuses a mismatch between how servers track active streams and how backends continue processing requests after stream resets. By flooding servers with server-sent resets while backend components keep working on abandoned streams, an attacker can force a single connection to consume unbounded CPU and memory resources, effectively bypassing SETTINGS_MAX_CONCURRENT_STREAMS limits. HTTP/2 MadeYouReset CVE-2025-8671 affects widely used implementations including Apache Tomcat, gRPC, Netty, Fastly, Varnish, and major Linux distributions from Red Hat and SUSE. Because many critical services terminate HTTP/2 at edge load balancers or API gateways, successful exploitation can degrade or knock offline multiple tenant environments simultaneously. The issue resembles the earlier Rapid Reset CVE-2023-44487, highlighting how lifecycle management for HTTP/2 streams remains fragile across implementations. Enterprises that rely on HTTP/2 for customer-facing sites, mobile backends, or microservices need to treat HTTP/2 MadeYouReset CVE-2025-8671 as an internet-wide reliability and availability risk. Even without data breach or code execution, sustained protocol abuse can disrupt revenue-generating services, critical business integrations, and public-sector portals. Mitigation requires both vendor patches and layered rate limiting on reset frames, combined with close collaboration between application, network, and security teams responsible for edge infrastructure.

🎯CORTEX Protocol Intelligence Assessment

Business Impact: HTTP/2 MadeYouReset CVE-2025-8671 creates an asymmetric attack condition in which moderately resourced adversaries can exhaust high-value web and API infrastructure. For SaaS providers, financial services, and critical industries that depend on low-latency HTTP/2 connections, successful exploitation can translate directly into downtime, SLA violations, and cascading operational impact across dependent workloads. Technical Context: HTTP/2 MadeYouReset CVE-2025-8671 manipulates server-sent stream resets so that protocol accounting considers streams closed while backend services continue processing. This gap allows attackers to exceed concurrency limits and drive resource exhaustion on application tiers. Apache Tomcat instances receive a dedicated CVE entry (CVE-2025-48989), and CERT/CC recommends stricter limits on RST_STREAM rates alongside implementation reviews. Organizations should monitor for anomalous reset behavior and apply vendor patches as they become available.

⚡Strategic Intelligence Guidance

Inventory all HTTP/2-enabled services, including reverse proxies, API gateways, and application servers, and map which products are affected by HTTP/2 MadeYouReset CVE-2025-8671.
Apply vendor patches and configuration updates for Apache Tomcat, Netty, gRPC, and other affected stacks as soon as they are released, prioritizing internet-exposed endpoints.
Implement network and application-layer rate limiting for RST_STREAM frames and anomalous HTTP/2 session behavior, and integrate these signals into DDoS protection workflows.
Test critical applications under HTTP/2 stress scenarios to validate resilience and update incident runbooks to cover protocol-level DoS attacks and failover strategies.

CVEs

CVE-2025-8671CVE-2025-48989CVE-2023-44487

Vendors

ApacheRed HatSUSEFastlyVarnish

Threats

HTTP/2 MadeYouResetHTTP/2 Rapid Reset

Targets

Web serversAPI gatewaysReverse proxies