Vulnerability Description
multer is a middleware for handling multipart/form-data in Node.js. A small multipart request containing two specially crafted text field names can cause an uncaught RangeError (Invalid array length) that terminates the Node.js process. The first field uses a very large numeric array index to allocate a maximum-length sparse array, and a second field then pushes past that length, which throws inside the append-field dependency and is not caught by multer. All versions before 2.3.0 are affected, and the issue is a remotely triggerable denial of service. The issue is fixed in multer 2.3.0. Upgrade to multer 2.3.0 to remediate.
CVSS Score
HIGH
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Expressjs | Multer | < 2.3.0 |
Related Weaknesses (CWE)
References
- https://cna.openjsf.org/security-advisories.htmlVendor Advisory
- https://github.com/expressjs/multer/security/advisories/GHSA-wc9g-mqfw-jrwmVendor Advisory
FAQ
What is CVE-2026-77078?
CVE-2026-77078 is a vulnerability with a CVSS score of 7.5 (HIGH). multer is a middleware for handling multipart/form-data in Node.js. A small multipart request containing two specially crafted text field names can cause an uncaught RangeError (Invalid array length) ...
How severe is CVE-2026-77078?
CVE-2026-77078 has been rated HIGH with a CVSS base score of 7.5/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-77078?
Check the references section above for vendor advisories and patch information. Affected products include: Expressjs Multer.