AIKIDO-2026-18568
multer is vulnerable to Denial of Service (DoS)
75
High Risk
This Affects:
multerTL;DR
Multer parses multipart form field names that use bracket notation into arrays. A request containing two specially crafted text field names can push past a maximum-length sparse array in the append-field dependency, throwing an uncaught RangeError during field parsing. Because the error escapes the application's error handlers, the Node.js process terminates and the service becomes unavailable. The fix rejects invalid field names with an INVALID_FIELD_NAME error instead of crashing.
Who does this affect?
You are affected if your application uses multer to parse multipart/form-data requests whose field names come from untrusted input.
Background info
multer is vulnerable to Denial of Service (DoS) in versions 0.0.1 - 2.2.0.
How to fix this
Upgrade the multer library to the patch version.
Links
GitHub Release
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