p PatchFirst

CVE-2026-77078

CVE-2026-77078 · multer vulnerable to Denial of Service via crafted multipart field names

This page contains facts from public vulnerability sources. Check the original advisory before updating.

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 7.5 · High · EPSS 0.5% · Fix available

Published
Updated

Stack: node

Affected products and versions

  • multer

    Versions
    • ≥ 0, < 2.3.0: Affected (semver)
    • 2.3.0: Not affected (semver)

    Update to 2.3.0

  • multer npm

    Affected ranges
    • SEMVER: < 2.3.0

    Update to 2.3.0

Original sources

Check your server →