VulnerabilityAnalyzed

CVE-2026-25224

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.

LOW 3.7EPSS 0.51%

Does this matter?

Lower severity and a low EPSS score (0.51%). Track it; it rarely justifies an emergency change on its own.

Description

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.

CVSS 3.1: 3.7 LOWCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L
EPSS: 0.51% probability · 42th percentile
CISA KEV: Not listed
Weakness: CWE-770
Affected: fastify/fastify
Source: security-advisories@github.com

References

https://github.com/fastify/fastify/commit/eb11156396f6a5fedaceed0140aed2b7f026be37Patch
https://github.com/fastify/fastify/security/advisories/GHSA-mrq3-vjjr-p77cVendor Advisory
https://hackerone.com/reports/3524779Permissions Required

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.