CVE-2026-19474: fastify fastify-multipart Incomplete Cleanup

Vulnerability summary

CVE-2026-19474 is a high (CVSS 7.5) Incomplete Cleanup vulnerability in fastify fastify-multipart. EPSS estimates a 0.49% chance of exploitation in the next 30 days, higher than 41.1% of scored vulnerabilities.

Timeline

1. 15-08-2026
   PublishedVulnerability first disclosed.
2. 17-08-2026
   Last modifiedVulnerability information updated.

Description

@fastify/multipart is a multipart form-data parser for Fastify. In versions from 3.0.0 up to but not including 10.1.1, request.saveRequestFiles() can leave completed temporary files on disk when a client disconnects while the parser is advancing between multipart parts. The iterator rejection that occurs between parts falls outside the per-file cleanup path, so an earlier completed file is never removed. An unauthenticated client can repeat this to cause persistent, linear disk consumption, leading to denial of service. This is an incomplete-fix variant of CVE-2025-24033. The issue is fixed in @fastify/multipart 10.1.1. Users should upgrade to 10.1.1.

• CWE-459Incomplete CleanupThe product does not properly "clean up" and remove temporary or supporting resources after they have been used.
• CWE-770Allocation of Resources Without Limits or ThrottlingThe product allocates a reusable resource or group of resources on behalf of an actor without imposing any intended restrictions on the size or number of resources that can be allocated.