CVE-2026-25224
low-risk
Published 2026-02-03
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.
Do I need to act?
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0.02% chance of exploitation
EPSS score — low exploit probability
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Not on CISA KEV list
No confirmed active exploitation reported to CISA
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Patch status unknown
Check vendor advisories for fix availability and mitigation guidance
3
CVSS 3.7/10
Low
NETWORK
/ HIGH complexity
Affected Products (1)
Fastify
Affected Vendors
References (3)
18
/ 100
low-risk
Severity
13/34 · Low
Exploitability
0/34 · Minimal
Exposure
5/34 · Minimal