Skip to main content

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


Severity High
Score 9.8/10


superjson is a program to allow JavaScript expressions to be serialized to a superset of JSON. In versions prior to (which includes v1.9.0-0) 1.8.1 superjson allows input to run arbitrary code on any server using superjson input without prior authentication or knowledge. The only requirement is that the server implements at least one endpoint which uses superjson during request processing. This has been patched in superjson 1.8.1. Users are advised to update. There are no known workarounds for this issue.

  • 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