CVE-2026-19474: @fastify/multipart vulnerable to Denial of Service via temporary file leak on aborted upload
@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.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
@fastify/multipartto a version that resolves this vulnerability.Fixed in 10.1.1
Event History
Frequently Asked Questions
What is the severity of CVE-2026-19474?
The severity of CVE-2026-19474 is classified as high with a score of 7.5.
What type of vulnerability is CVE-2026-19474?
CVE-2026-19474 is a Denial of Service vulnerability caused by a temporary file leak on aborted uploads.
How does CVE-2026-19474 affect @fastify/multipart?
CVE-2026-19474 affects @fastify/multipart by allowing temporary files to remain on disk when a client disconnects during file uploads.
What versions of @fastify/multipart are affected by CVE-2026-19474?
Versions of @fastify/multipart from 3.0.0 up to but not including 10.1.1 are affected by CVE-2026-19474.
How do I fix CVE-2026-19474?
To fix CVE-2026-19474, update @fastify/multipart to version 10.1.1 or later.