multer vulnerable to file size limit bypass via async fileFilter race condition
En bref
Sévérité
LOW 3.7
EPSS
EPSS 0.23 % · centile 14 (2026-10-27)
État
PUBLISHED
Publiée
Mise à jour
Attribuée par
openjs
Statut NVD
Analyzed
Description
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.
