CVE-2026-5079

Impact: multer versions 1.0.0 through 2.1.1 and 3.0.0-alpha.1 are vulnerable to a Denial of Service via deeply nested field names in multipart form data. The append-field dependency parses bracket notation in field names with no limit on nesting depth, allowing an attacker to force allocation of deeply nested object structures that consume CPU and memory. A single HTTP request with a crafted multipart body is sufficient to exploit this. Patches: Users should upgrade to multer 2.2.0 (2.x line) or 3.0.0-alpha.2 (3.x prerelease) and configure the new limits.fieldNestingDepth option to the minimum depth their application requires. Workarounds: Set limits.fields to a reasonable value to reduce the number of fields an attacker can send per request. This does not fully mitigate the issue but limits the impact.

CVSS v3 7.5 HIGH

7.5^/10

CVSS v3 : HIGH

Vector :

Exploitability : 3.9 / Impact : 3.6

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact NONE

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
https://cna.openjsf.org/security-advisories.html	Vendor Advisory
https://github.com/expressjs/multer/security/advisories/GHSA-72gw-mp4g-v24j	Mitigation Vendor Advisory

Configurations

Configuration 1 (hide)

OR	cpe:2.3:a:expressjs:multer::::::node.js::*
	cpe:2.3:a:expressjs:multer:3.0.0:alpha1::::node.js::*

History

16 Jun 2026, 16:49

Type	Values Removed	Values Added
First Time		Expressjs multer Expressjs
References	~~() https://cna.openjsf.org/security-advisories.html -~~	() https://cna.openjsf.org/security-advisories.html - Vendor Advisory
References	~~() https://github.com/expressjs/multer/security/advisories/GHSA-72gw-mp4g-v24j -~~	() https://github.com/expressjs/multer/security/advisories/GHSA-72gw-mp4g-v24j - Mitigation, Vendor Advisory
CPE		cpe:2.3:a:expressjs:multer:3.0.0:alpha1::::node.js::* cpe:2.3:a:expressjs:multer::::::node.js::*

15 Jun 2026, 14:16

Type	Values Removed	Values Added
New CVE

Information

Published : 2026-06-15 14:16

Updated : 2026-06-17 10:58

NVD link : CVE-2026-5079

Mitre link : CVE-2026-5079

CVE.ORG link : CVE-2026-5079

JSON object : View

Products Affected

expressjs

multer

CWE

CWE-400

Uncontrolled Resource Consumption

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