GHSA-m7rc-8w7m-r9qr: SurrealDB vulnerable to memory exhaustion via nested functions and scripts

In order to prevent DoS situations due to infinite recursions, SurrealDB implements a limit of nested calls for both native functions and embedded JavaScript functions.

However, in SurrealDB instances with embedded scripting functions enabled, it was found that this limit can be circumvented by utilizing both at the same time. If a native function contains JavaScript which issues a new query that calls that function, the recursion limit is not triggered.

Once executed, SurrealDB will follow the path of infinite recursions until the system runs out of memory, prior to the recursion limit being triggered.

This vulnerability can only affect SurrealDB servers explicitly enabling the scripting capability with --allow-scripting or --allow-all and equivalent environment variables SURREAL_CAPS_ALLOW_SCRIPT=true and SURREAL_CAPS_ALLOW_ALL=true.

This issue was discovered and patched during an code audit and penetration test of SurrealDB by cure53, the severity defined within cure53’s preliminary finding is Medium, matched by our CVSS v4 assessment.