CVE-2026-77063

multer is a middleware for handling multipart/form-data in Node.js. When an application uses an asynchronous fileFilter together with the fileSize limit, a race condition in multer's file stream handling can allow a file that exceeds the configured size limit to bypass the size-limit rejection. All versions before 2.3.0 are affected. The impact is limited because the underlying multipart parser still truncates the stream at the size limit, so this is a bypass of the limit rejection rather than uncontrolled resource consumption. The issue is fixed in multer 2.3.0. Upgrade to multer 2.3.0 to remediate.

CVSS v3 3.7 LOW

3.7^/10

CVSS v3 : LOW

Vector :

Exploitability : 2.2 / Impact : 1.4

Attack Vector NETWORK

Attack Complexity HIGH

Privileges Required NONE

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact LOW

Availability Impact NONE

Scope UNCHANGED

References

Link	Resource
https://cna.openjsf.org/security-advisories.html	Vendor Advisory
https://github.com/expressjs/multer/security/advisories/GHSA-qvfw-j98x-7q72	Vendor Advisory Mitigation

Configurations

Configuration 1 (hide)

cpe:2.3:a:expressjs:multer:*:*:*:*:*:node.js:*:*

History

No history.

Information

Published : 2026-08-28 22:16

Updated : 2026-09-02 14:46

NVD link : CVE-2026-77063

Mitre link : CVE-2026-77063

CVE.ORG link : CVE-2026-77063

JSON object : View

Products Affected

expressjs

multer

CWE

CWE-362

Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')

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