multer vulnerable to Denial of Service via crafted multipart field names
At a glance
Severity
HIGH 7.5
EPSS
EPSS 0.49 % · percentile 42 (2026-10-27)
State
PUBLISHED
Published
Updated
Assigner
openjs
NVD status
Analyzed
Description
multer is a middleware for handling multipart/form-data in Node.js. A small multipart request containing two specially crafted text field names can cause an uncaught RangeError (Invalid array length) that terminates the Node.js process. The first field uses a very large numeric array index to allocate a maximum-length sparse array, and a second field then pushes past that length, which throws inside the append-field dependency and is not caught by multer. All versions before 2.3.0 are affected, and the issue is a remotely triggerable denial of service. The issue is fixed in multer 2.3.0. Upgrade to multer 2.3.0 to remediate.
