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


Severity High
Score 9.8/10


A vulnerability, which was classified as critical, was found in hughsk flat versions prior to 1.6.2, 2.0.x prior to 2.0.2, 3.0.x prior to 3.0.1, 4.0.x prior to 4.1.1, and 5.0.x prior to 5.0.1. This affects the function "unflatten" of the file "index.js". The manipulation leads to improperly controlled modification of object prototype attributes ('prototype pollution'). It is possible to initiate the attack remotely. It is recommended to upgrade the affected component. The identifier VDB-216777 was assigned to this vulnerability.

  • 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