GHSA-prg7-hcfm-mfcr: sqlparse: Inefficient Regex Handling of Dollar-Quoted SQL Literals Leads to ReDoS (Denial of Service)

sqlparse has a ReDoS (regular expression denial of service) vulnerability in how it handles dollar-quoted SQL literals. The vulnerable regex pattern uses a backreference to match closing delimiters, but when closing delimiters don't exist, it scans the entire remaining input, causing O(n²) CPU complexity (meaning time grows quadratically with input size). An attacker can exploit this by sending specially crafted SQL text to any application using sqlparse, causing the application to consume excessive CPU and become unresponsive.