CVE-2026-45302 PUBLISHED

Prototype Pollution in parse-nested-form-data via `__proto__` in FormData field names

Assigner: GitHub_M
Reserved: 11.05.2026 Published: 01.06.2026 Updated: 02.06.2026

parse-nested-form-data is a tiny node module for parsing FormData by name into objects and arrays. Prior to version 1.0.1, parseFormData() walks bracket and dot-notation FormData field names into nested objects without filtering reserved property keys. A single FormData field whose name begins with proto, or contains .proto. mid-path, causes the parser to traverse onto Object.prototype and assign properties there, polluting the prototype chain of every plain object in the running process. This issue has been patched in version 1.0.1.

Metrics

CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:L
CVSS Score: 8.2

Product Status

Vendor milamer
Product parse-nested-form-data
Versions
  • Version < 1.0.1 is affected

References

Problem Types

  • CWE-1321: Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution') CWE