Impact

Internal fields (keys used internally by Parse Server, prefixed by _) and protected fields (user defined) can be used as query constraints. Internal and protected fields are removed by Parse Server from query results and are only returned to the client using a valid master key. However, using query constraints, these fields can be guessed by enumerating until Parse Server returns a response object.

Patches

The patch requires the master key to use internal and protected fields as query constraints.

Workarounds

Implement a Parse Cloud Trigger beforeFind and manually remove the query constraints, such as:

Parse.Cloud.beforeFind('TestObject', ({ query }) => {
  for (const key in query._where || []) {
    // Repeat logic for protected fields
    if (key.charAt(0) === '_') {
      delete query._where[key];
    }
  }
});

References

• GHSA-2m6g-crv8-p3c6