CVE-2026-45302

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

Published Jun 1, 2026 CVSS 3.1 · 8.2 High EPSS < 1% KEV · Not listed
Description
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Github GHSA Github GHSA GHSA-xp7r-j8r6-j9h3 parse-nested-form-data has Prototype Pollution via `__proto__` in FormData field names
History
Type Values Removed Values Added
First Time appeared Milamer
Milamer parse-nested-form-data
Vendors & Products Milamer
Milamer parse-nested-form-data
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
Description 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.
Title Prototype Pollution in parse-nested-form-data via `__proto__` in FormData field names
Weaknesses CWE-1321
References
Metrics cvssV3_1

{'score': 8.2, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:L'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
GitHub_M
Published
Updated
Jun 2, 2026, 2:45 PM
Reserved
May 11, 2026, 8:14 PM
Status
Deferred
Published
Jun 1, 2026, 7:16 PM
Modified
Jul 22, 2026, 8:10 AM