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CVE-2026-25224

Fastify Vulnerable to DoS via Unbounded Memory Allocation in sendWebStream

Published: Feb 3, 2026Updated: Feb 10, 2026 Sources: CVE List NVD GHSACWE-770
NVD MITRE
3.7CVSSLOW
EPSS Score
0.5%
Top 61.9%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
Patch Available

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 Vector Breakdown

AV:NAC:HPR:NUI:NS:UC:NI:NA:L
Exploitability
AV:NAttack Vector
Network
AC:HAttack Complexity
High
PR:NPrivileges Required
None
UI:NUser Interaction
None
Scope
S:UScope
Unchanged
Impact
C:NConfidentiality
None
I:NIntegrity
None
A:LAvailability
Low
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Weaknesses

CWE-770

Affected Products

fastifyfastify
Library
OSS Libraries / web-framework
fastifynpmOSS Libraries
fastifyoss-projectOSS Librariesaka fastify/middie, fastify-multipart
npmpackage-ecosystemOSS Libraries

Attack Graph

Products CVE Techniques Tactics

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Exploitability

Official Patch Available

MITRE ATT&CK

1 technique
Impact
View detailed technique mapping

References

https://github.com/fastify/fastify/commit/eb11156396f6a5fedaceed0140aed2b7f026be37
github.com
https://github.com/fastify/fastify/security/advisories/GHSA-mrq3-vjjr-p77c
github.com
https://hackerone.com/reports/3524779
hackerone.com
and 2 more references View all →

Timeline

Published
Feb 3, 2026
Last Updated
Feb 10, 2026

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