Description
In parser-server before version 4.1.0, you can fetch all the users objects, by using regex in the NoSQL query. Using the NoSQL, you can use a regex on sessionToken and find valid accounts this way.
Remediation
References
https://github.com/parse-community/parse-server/commit/3a3a5eee5ffa48da1352423312cb767de14de269
https://github.com/parse-community/parse-server/security/advisories/GHSA-h4mf-75hf-67w4