Incomplete Cleanup Affecting @fastify/multipart package, versions <10.1.1
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.
Do your applications use this vulnerable package?
In a few clicks we can analyze your entire application and see what components are vulnerable in your application, and suggest you quick fixes.
Test your applications- Snyk IDSNYK-JS-FASTIFYMULTIPART-18853754
- published16 Aug 2026
- disclosed15 Aug 2026
- creditHemanth-9087
Introduced: 15 Aug 2026
NewCVE-2026-19474 (opens in a new tab)How to fix?
Upgrade @fastify/multipart to version 10.1.1 or higher.
Overview
@fastify/multipart is a Multipart plugin for Fastify
Affected versions of this package are vulnerable to Incomplete Cleanup due to incomplete temporary-file handling in saveRequestFiles() in index.js. An attacker can exhaust disk space by sending a multipart request that completes one file part, starts a later part, and then disconnects before the upload finishes. When saveRequestFiles() rejects while advancing to the next part, the already-written temporary files are left on disk instead of being removed. Repeating this against a route that accepts multiple multipart parts causes unbounded temp-file growth and can disrupt the application by filling the filesystem.
Workarounds
- Call
request.cleanRequestFiles()whensaveRequestFiles()rejects, so already-completed temporary files are removed after an aborted multipart upload instead of accumulating on disk.