GHSA-72gw-mp4g-v24j
Multer vulnerable to Denial of Service via deeply nested field names
Quick fix
GHSA-72gw-mp4g-v24j — multer: upgrade to the fixed version with the command below.
npm install multer@2.2.0Details
### Impact
Multer is vulnerable to a Denial of Service (DoS) via deeply nested field names in multipart form data. The `append-field` dependency parses bracket notation in field names (e.g., `a[b][c]`) with no limit on nesting depth, allowing an attacker to force allocation of deeply nested object structures that consume CPU and memory. A single HTTP request with a crafted multipart body is sufficient to exploit this.
### Patches
Users should upgrade to `2.2.0` and configure `limits.fieldNestingDepth` to the minimum depth their application requires.
### Workarounds
Set `limits.fields` to a reasonable value to reduce the number of fields an attacker can send per request. This does not fully mitigate the issue but limits the impact.
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