Allocation of Resources Without Limits or Throttling Affecting fastify package, versions <5.7.3
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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- published3 Feb 2026
- disclosed2 Feb 2026
- creditUnknown
Introduced: 2 Feb 2026
NewCVE-2026-25224 (opens in a new tab)How to fix?
Upgrade fastify to version 5.7.3 or higher.
Overview
fastify is an overhead web framework, for Node.js.
Affected versions of this package are vulnerable to Allocation of Resources Without Limits or Throttling via the sendWebStream function. An attacker can cause excessive memory consumption by sending a slow or non-reading client request, leading to unbounded buffering and severe performance degradation or process crashes.
Note: Only applications that return a ReadableStream (or Response with a Web Stream body) via reply.send() are impacted
Workaround
This vulnerability can be mitigated by avoiding Fastify Web Streams in responses and instead using Node.js streams or buffered payloads.