SQLFluff: Recursive Stack Overflow in Parser

Impact

In deployments where untrusted users can provide SQL queries to be linted, an untrusted user can submit a malicious query with deliberate excessive nesting to any application using the parser to trigger a Denial of Service through resource exhaustion.

Patches

Versions 4.1.0 and up contain a configurable recursion limit, which is enabled by default, to prevent this manner of exploit.

Credit

Ori Nakar from Imperva Threat Research Team.