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8.7
Malformed Requests Can Crash Multer Server
CVE-2026-3520
GHSA-5528-5vmv-3xc2
GHSA-5528-5vmv-3xc2
Summary
Multer, a tool used to handle file uploads, has a weakness that can cause a server to crash if it receives a specially crafted file. This could make your website or application unavailable. To fix this, update Multer to the latest version.
What to do
- Update ulisesgascon multer to version 2.1.1.
Affected software
| Vendor | Product | Affected versions | Fix available |
|---|---|---|---|
| ulisesgascon | multer | <= 2.1.1 | 2.1.1 |
| expressjs | multer | <= 2.1.1 | – |
Original title
Multer is a node.js middleware for handling `multipart/form-data`. A vulnerability in Multer prior to version 2.1.1 allows an attacker to trigger a Denial of Service (DoS) by sending malformed requ...
Original description
Multer is a node.js middleware for handling `multipart/form-data`. A vulnerability in Multer prior to version 2.1.1 allows an attacker to trigger a Denial of Service (DoS) by sending malformed requests, potentially causing stack overflow. Users should upgrade to version 2.1.1 to receive a patch. No known workarounds are available.
nvd CVSS4.0
8.7
Vulnerability type
CWE-674
- https://nvd.nist.gov/vuln/detail/CVE-2026-3520
- https://cna.openjsf.org/security-advisories.html
- https://github.com/expressjs/multer/commit/7e66481f8b2e6c54b982b34c152479e096ce2...
- https://github.com/expressjs/multer/security/advisories/GHSA-5528-5vmv-3xc2
- https://www.cve.org/CVERecord?id=CVE-2026-3520
- https://github.com/advisories/GHSA-5528-5vmv-3xc2
- https://github.com/expressjs/multer Product
Published: 4 Mar 2026 · Updated: 13 Mar 2026 · First seen: 6 Mar 2026