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 Metrics
- Vector
- CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L
- Attack Vector
- network
- Complexity
- high
- Privileges
- none
- User Action
- none
- Scope
- unchanged
- Confidentiality
- none
- Integrity
- none
- Availability
- low
- Weaknesses
- CWE-770
Metadata
- Primary Vendor
- FASTIFY
- Published
- 2/3/2026
- Last Modified
- 2/10/2026
- Source
- NIST NVD
- Note: Verify all details with official vendor sources before applying patches.
Affected Products
fastify : fastify
AI-Powered Remediation
Generate remediation guidance or a C-suite brief for this vulnerability.