Resource exhaustion in multer - CVE-2026-82333
Published: September 2, 2026
Vulnerability identifier: #VU146778
CSH Severity: Medium
CVSS v4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-82333
CWE-ID: CWE-400
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to cause a denial of service.
The vulnerability exists due to uncontrolled resource consumption in the append-field dependency used by multer when parsing multipart field names with crafted bracket notation. A remote attacker can send a specially crafted HTTP request with an oversized array index in a field name to cause a denial of service.
A single crafted multipart request is sufficient to trigger synchronous CPU consumption that prevents the process from handling other requests.
Affected software
multer
How to mitigate CVE-2026-82333
Install security update from vendor's website.
multer - update to 2.3.0