Bug 2436557 (CVE-2026-25224)

Summary: CVE-2026-25224 Fastify: Fastify: Denial of Service via unbounded buffering in Web Streams response handling
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
Status: NEW --- QA Contact:
Severity: low Docs Contact:
Priority: low    
Version: unspecifiedCC: bbrownin, jkoehler, lphiri, sdawley
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in Fastify. A remote client can exploit this denial-of-service vulnerability by sending a slow or non-reading request when the application returns a ReadableStream (or Response with a Web Stream body) via reply.send(). This can lead to unbounded buffering, exhausting server memory. The consequence is a Denial of Service (DoS), potentially causing process crashes or severe degradation of the server.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Description OSIDB Bzimport 2026-02-03 22:01:30 UTC 
Fastify is a fast and low overhead web framework, for Node.js. Prior to version 5.7.3, a denial-of-service vulnerability in Fastify’s Web Streams response handling can allow a remote client to exhaust server memory. Applications that return a ReadableStream (or Response with a Web Stream body) via reply.send() are impacted. A slow or non-reading client can trigger unbounded buffering when backpressure is ignored, leading to process crashes or severe degradation. This issue has been patched in version 5.7.3.