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GHSA-vpj2-qq7w-5qq6
No affected components available
Impact
An attacker can bypass Cloud Function validator access controls by appending .prototype.constructor to the function name in the URL. When a Cloud Function handler is declared using the function keyword and its validator is a plain object or arrow function, the trigger store traversal resolves the handler through its own prototype chain while the validator store fails to mirror this traversal, causing all access control enforcement to be skipped.
This allows unauthenticated callers to invoke Cloud Functions that are meant to be protected by validators such as requireUser, requireMaster, or custom validation logic.
Patches
The trigger store traversal now verifies that each intermediate node is a legitimate store object before continuing traversal. If the traversal encounters a non-store value such as a function handler, it stops and returns an empty store, preventing prototype chain escape.
Workarounds
Use arrow functions instead of the function keyword for Cloud Function handlers. Arrow functions do not have a prototype property and are not affected by this vulnerability.
Resources
- GitHub security advisory: https://github.com/parse-community/parse-server/security/advisories/GHSA-vpj2-qq7w-5qq6
- Fix Parse Server 9: https://github.com/parse-community/parse-server/pull/10342
- Fix Parse Server 8: https://github.com/parse-community/parse-server/pull/10343
The vulnerability can be exploited over the network without needing physical access. It is easy for an attacker to exploit this vulnerability. An attacker does not need any special privileges or access rights. No user interaction is needed for the attacker to exploit this vulnerability.
Exploitation attempts have been detected. Elevated vigilance and prompt remediation are advised.
The exploit probability is very low. The vulnerability is unlikely to be exploited in the next 30 days.
We did not find any exploit available. Neither in GitHub repositories nor in the Exploit-Database.
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