GHSA-mrq3-vjjr-p77c
Fastify Vulnerable to DoS via Unbounded Memory Allocation in sendWebStream
Quick fix
GHSA-mrq3-vjjr-p77c — fastify: upgrade to the fixed version with the command below.
npm install fastify@5.7.3Details
### Impact 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.
### Patches The issue is fixed in Fastify 5.7.3. Users should upgrade to 5.7.3 or later.
### Workarounds Avoid sending Web Streams from Fastify responses (e.g., `ReadableStream` or `Response` bodies). Use Node.js streams (`stream.Readable`) or buffered payloads instead until the project can upgrade.
### References - https://hackerone.com/reports/3524779
Are you affected?
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Affected packages
References
- https://github.com/fastify/fastify/security/advisories/GHSA-mrq3-vjjr-p77c[WEB]
- https://nvd.nist.gov/vuln/detail/CVE-2026-25224[ADVISORY]
- https://github.com/fastify/fastify/commit/eb11156396f6a5fedaceed0140aed2b7f026be37[WEB]
- https://hackerone.com/reports/3524779[WEB]
- https://github.com/fastify/fastify[PACKAGE]