multer throws "File too large" error if file size of exact "limits.fileSize" bytes provided.

[ho94949]

Multer throws "File too large" error if file size of exat "limits.fileSize" bytes provided. It is non-intuitive behavior. (Or it might be a corner-case.)

It seems that busboy emits event "limit" when limits.fileSize bytes is hit. However, this means that busboy will not further process files, and it might be truncated.

multer/lib/make-middleware.js

Lines 153 to 156 in 2e07e77

	fileStream.on('limit', function () {
	aborting = true
	abortWithCode('LIMIT_FILE_SIZE', fieldname)
	})

Relevant lines in busboy: https://github.com/mscdex/busboy/blob/6b3dcf69d38c1a8d53a0b3e4c88ba296f6c91525/lib/types/multipart.js#L476-L482

Current Workaround

increase limits.fileSize by 1.

Environment information

Version:
To find the installed version of a package, you can check the package.json file in the root directory of your project. The version will be listed under dependencies or devDependencies, like this:

"dependencies": {
    // ...
    "express": "^5.1.0",
    "multer": "^2.0.2",
    // ...
}

Platform:
Linux NX-281041 6.6.87.2-microsoft-standard-WSL2 #1 SMP PREEMPT_DYNAMIC Thu Jun 5 18:30:46 UTC 2025 x86_64 x86_64 x86_64 GNU/Linux

Node.js version:
v22.16.0