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CVE-2026-45302

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

CVSS 8.2 HIGHEPSS 0.3%CWE-1321
Vexday Risk Score
21Low
SSVC decision (CISA)
Track
No exploitation signal → monitor
CVSS 8.2EPSS 0.3%KEV nãoPoC Nuclei Metasploit Patch
Lifecycle
01 Jun 2026Published on NVD
Recommendation: Monitor — no exploitation signal at the moment.
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.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:L

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