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


Severity High
Score 9.8/10


Parse Server is an open source backend that can be deployed to any infrastructure that can run Node.js. In versions prior to 4.10.20, 5.0.x prior to 5.3.3, and 5.4.x prior to 5.4.0, a compromised Parse Server Cloud Code Webhook target endpoint allows an attacker to use prototype pollution to bypass the Parse Server `requestKeywordDenylist` option. This issue has been patched in versions 5.3.3 and 4.10.20. There are no known workarounds.

  • LOW
  • HIGH
  • NONE
  • NONE
  • HIGH
  • HIGH

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.

Advisory Timeline

  • Published