Affected versions of the sqlparse package are vulnerable to Denial of Service (DoS) due to missing hard limits on token grouping recursion depth and token processing when formatting very large SQL tuple lists. During sqlparse.format() processing, the sqlparse.engine.grouping._group_matching() and sqlparse.engine.grouping._group() functions can recurse and iterate over excessively large tlist.tokens without enforcing MAX_GROUPING_DEPTH or MAX_GROUPING_TOKENS, allowing grouping work to grow until it effectively hangs.

Affected versions of this package are vulnerable to Denial of Service (DoS) attacks due to Algorithmic Complexity. The SQL parser fails to enforce limits when processing deeply nested tuples and large token sequences, leading to excessive resource consumption through crafted SQL statements with extreme nesting depth or token counts.

**Note:** This issue is due to an incomplete fix for CVE-2024-4340.

Sqlparse 0.5.0 addresses a potential denial of service (DoS) vulnerability related to recursion errors in deeply nested SQL statements. To mitigate this issue, the update replaces recursion errors with a general SQLParseError, improving the resilience and stability of the parsing process.

Sqlparse 0.4.4 includes a fix for CVE-2023-30608: Parser contains a regular expression that is vulnerable to ReDOS (Regular Expression Denial of Service).
https://github.com/andialbrecht/sqlparse/security/advisories/GHSA-rrm6-wvj7-cwh2