CVE-2026-45302
CVE-2026-45302 is a high-severity vulnerability with a CVSS 3.x base score of 8.2. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-1321.
Key facts
- Severity: High (CVSS 3.x base score 8.2)
- EPSS exploit prediction: 0% (23rd percentile)
- Actively exploited: Not listed in CISA KEV
- EU (EUVD) id: EUVD-2026-33723
- Weakness: CWE-1321
- Published:
- Last modified:
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.
Frequently asked questions
- What is CVE-2026-45302?
- 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.
- How severe is CVE-2026-45302?
- CVE-2026-45302 has a CVSS 3.x base score of 8.2, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability low.
- Is CVE-2026-45302 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (23rd percentile), an estimate of the probability of exploitation in the next 30 days.
- How do I fix CVE-2026-45302?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
- Does CVE-2026-45302 have an EU (EUVD) identifier?
- Yes. CVE-2026-45302 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-33723.
- When was CVE-2026-45302 published?
- CVE-2026-45302 was published on 2026-06-01 and last updated on 2026-06-17.
References
- https://github.com/milamer/parse-nested-form-data/commit/527ad58eb486e32438f7198fb88315c20449d792
- https://github.com/milamer/parse-nested-form-data/releases/tag/v1.0.1
- https://github.com/milamer/parse-nested-form-data/security/advisories/GHSA-xp7r-j8r6-j9h3
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