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Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution')

CVE-2026-45302

Low
0/10

Summary

A vulnerability has been found in parse-nested-form-data versions prior to 1.0.1. The `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.

  • LOW
  • NETWORK
  • HIGH
  • UNCHANGED
  • NONE
  • NONE
  • NONE
  • LOW

CWE-1321 - Prototype Pollution

Prototype pollution is one of the lesser-known vulnerabilities. It allows attackers to abuse the rules of JavaScript by injecting properties into the general object “Object” in JS. Modifying the prototype of “Object” affects the behavior of all objects in the entire app, potentially resulting in denial of service, arbitrary code execution, cross-site scripting, etc.

References

Advisory Timeline

  • Published