What’s Vulnerable › Vulnerabilities

CVE-2026-19474: @fastify/multipart vulnerable to Denial of Service via temporary file leak on aborted upload

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.5% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-08-15 · updated 2026-09-02
• Weakness: CWE-459

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.

Affected products

• fastify-multipart: from 3.0.0 before 10.1.1 — fixed in 10.1.1

How to fix

Upgrade to a fixed version: fastify-multipart 10.1.1. Check the vendor advisory for mitigations.

References

• https://cna.openjsf.org/security-advisories.html
• https://github.com/fastify/fastify-multipart/security/advisories/GHSA-62qx-hpj5-j6hc

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