CVE-2026-18549@fastify/multipart vulnerable to Denial of Service via aborted upload after fileSize limit
Updated under an hour ago ()
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It affects @fastify/multipart and 1 other product. Add what you run to find out whether that includes you.
No exploitation reported and no EPSS estimate yet.
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@fastify/multipart is a multipart form-data parser for Fastify. In versions from 5.3.0 up to but not including 10.1.1, when the busboy fileSize limit truncates a file part, the plugin clears its internal current-file reference while the underlying stream is still open. If the client then aborts the connection before sending the terminating boundary, the abort cleanup finds no stream to destroy, so saveRequestFiles() never settles, the request handler hangs, and the temporary file already written to disk is never cleaned up. An unauthenticated client can repeat this to permanently leak temporary files and suspended handler executions, leading to disk and event-loop exhaustion. The issue is fixed in @fastify/multipart 10.1.1. Users should upgrade to 10.1.1.
- CVSS
- 7.5 HIGH (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- Weakness (CWE)
- CWE-400, CWE-664
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- openjs
- NVD analysis
- Analyzed
- Record last updated
- Aug 17, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
@fastify/multipart @fastify/multipart fastify_multipart:fastify_multipart (from the name) | from 5.3.0 before 10.1.1; 10.1.1 not affected | CNA record |
fastify fastify-multipart fastify:fastify-multipart | from 5.3.0 before 10.1.1 | NVD |
References
- https://github.com/fastify/fastify-multipart/security/advisories/GHSA-vmph-573x-85f6mitigation, vendor-advisory
- https://cna.openjsf.org/security-advisories.htmlthird-party-advisory
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.