high

CVE-2026-82333

npm · multer

Summary

multer vulnerable to Denial of Service via oversized array index in field names

Severity
high
CVSS
7.5
EPSS
0.3% (p20)
CWE
CWE-400
Also known as
GHSA-535w-7cp7-47q4
Published
2026-09-08
Updated
2026-09-08

Advisory details

Impact

multer is vulnerable to a Denial of Service (DoS) via a crafted array index in multipart field names. The append-field dependency parses bracket notation in field names, and a large numeric index such as items[4294967294] forces allocation of a maximum-length sparse array. A following field with a non-numeric key on the same base then converts that array to an object by iterating its full length, which consumes CPU synchronously and leaves the process unable to handle other requests. A single HTTP request with a crafted multipart body is sufficient to exploit this, and it affects multer 1.x and 2.x.

Patches

Users should upgrade to 2.3.0 and configure limits.fieldArrayIndexLimit to the minimum array index their application requires.

Workarounds

None.

References

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Sources: CISA KEV (public domain), OSV.dev & GitHub Advisory Database (CC-BY-4.0), FIRST EPSS, NVD/CWE (public domain). Served live from the Stateward advisory database.