Vulnerability-Lookup

CVE-2026-18549 (GCVE-0-2026-18549)

Vulnerability from cvelistv5 – Published: 2026-08-15 13:26 – Updated: 2026-08-17 19:44

Title

@fastify/multipart vulnerable to Denial of Service via aborted upload after fileSize limit

Summary

@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.

Severity

7.5 (High)


                        
                          CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

SSVC

Exploitation: none Automatable: yes Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-08-17 19:43 UTC

CWE

CWE-400 - Uncontrolled Resource Consumption
CWE-664 - Improper Control of a Resource Through its Lifetime

Assigner

openjs redhat root

References

2 references

URL	Tags
https://github.com/fastify/fastify-multipart/secu…
https://cna.openjsf.org/security-advisories.html

Impacted products

1 product

Vendor	Product	Version	CPE status
@fastify/multipart	@fastify/multipart	Affected: 5.3.0 , < 10.1.1 (semver) Unaffected: 10.1.1 (semver)	guessed

Credits

iaohkut-from-NightWolf-Team UlisesGascon mcollina

Show details on NVD website

JSON

To clipboard

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FKIE_CVE-2026-18549

Vulnerability from fkie_nvd - Published: 2026-08-15 14:17 - Updated: 2026-08-17 20:16

Severity

7.5 (High) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Summary

References

	URL	Tags
	ce714d77-add3-4f53-aff5-83d477b104bb	https://cna.openjsf.org/security-advisories.html
	ce714d77-add3-4f53-aff5-83d477b104bb	https://github.com/fastify/fastify-multipart/security/advisories/GHSA-vmph-573x-85f6

Impacted products

	Vendor	Product	Version

JSON

To clipboard

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  ],
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Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.

Action not permitted

CVE-2026-18549 (GCVE-0-2026-18549)

FKIE_CVE-2026-18549

Tags

Sightings

Nomenclature