Prototype pollution via reserved-key path traversal
Published Jun 1, 2026 · Updated Jun 1, 2026
Prototype pollution in handlePathPart in parse-nested-form-data before 1.0.1 allows remote attackers to modify Object.prototype. The function reads an untrusted proto path segment, traverses into Object.prototype, and assigns the next field value there. Reachability requires a host application to pass attacker-controlled FormData to parseFormData(); the mutation can corrupt application state, alter control flow, or interrupt the service.
Summary
What happened
Prototype pollution in handlePathPart in parse-nested-form-data before 1.0.1 allows remote attackers to modify Object.prototype. The function reads an untrusted proto path segment, traverses into Object.prototype, and assigns the next field value there. Reachability requires a host application to pass attacker-controlled FormData to parseFormData(); the mutation can corrupt application state, alter control flow, or interrupt the service.
The record
- CVE
- CVE-2026-45302
- Published
- Jun 1, 2026
- Updated
- Jun 1, 2026
- Vendor
- milamer
- Product
- parse-nested-form-data
- Classifications
- CWE-1321, T1190
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jun 1, 2026CVE publishedPublication date reported by the CVE source.
- Jun 1, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=< 1.0.1
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- GitHub advisory prototype-pollution reproductionproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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