CVE-2026-117531 (GCVE-0-2026-117531)
Vulnerability from cvelistv5 – Published: 2026-11-02 10:32 – Updated: 2026-11-02 16:58
VLAI
EPSS
VEX
Title
@fastify/multipart vulnerable to Denial of Service via a malformed upload hanging delayed file consumers
Summary
@fastify/multipart is the multipart form-data and file upload plugin for the Fastify web framework. In versions 5.3.0 through 10.1.6, the plugin does not propagate a parser error to the file stream when a request body ends inside a file part with no closing boundary, even though the Content-Length is complete, the client does not abort, and no file size limit is exceeded. The plugin destroys the in-progress file stream without an error, so a handler that iterates the request parts and performs asynchronous work before consuming the file attaches to a stream that never emits an error or end event, and the request never responds while the connection stays open. An unauthenticated remote client can repeat these malformed uploads against such a route to accumulate pending connections and exhaust server resources, so the impact is availability only and exploitation depends on the application using a delayed file consumer. The issue is fixed in @fastify/multipart 10.1.7, where the parser error is propagated to the file stream so a delayed consumer settles with an error instead of hanging, and users should upgrade to 10.1.7 or later. There is no workaround other than upgrading.
Severity
5.9 (Medium)
SSVC
Exploitation: none
Automatable: no
Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-11-02 16:58 UTC
CWE
- CWE-400 - Uncontrolled Resource Consumption
Assigner
References
Impacted products
1 product
| Vendor | Product | Version | CPE status | |
|---|---|---|---|---|
| @fastify/multipart | @fastify/multipart |
Affected:
5.3.0 , < 10.1.7
(semver)
Unaffected: 10.1.7 (semver) |
guessed |
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