CVE-2026-25224

Fastify Vulnerable to DoS via Unbounded Memory Allocation in sendWebStream

Published Feb 3, 2026 CVSS 3.1 · 3.7 Low EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Github GHSA Github GHSA GHSA-mrq3-vjjr-p77c Fastify Vulnerable to DoS via Unbounded Memory Allocation in sendWebStream
History
Type Values Removed Values Added
CPEs cpe:2.3:a:fastify:fastify:*:*:*:*:*:node.js:*:*
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
First Time appeared Fastify
Fastify fastify
Vendors & Products Fastify
Fastify fastify
References
Metrics threat_severity

None

threat_severity

Low

Type Values Removed Values Added
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.
Title Fastify Vulnerable to DoS via Unbounded Memory Allocation in sendWebStream
Weaknesses CWE-770
References
Metrics cvssV3_1

{'score': 3.7, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
GitHub_M
Published
Updated
Feb 4, 2026, 4:20 PM
Reserved
Jan 30, 2026, 2:44 PM
Status
Analyzed
Published
Feb 3, 2026, 10:16 PM
Modified
Jun 17, 2026, 10:24 AM
Severity
Low
Public date
Feb 3, 2026, 9:21 PM