CVE-2026-54284 sqlparse: TokenList.__init__ materializes O(subtree) value per group, causing CPU DoS before depth/token caps trigger

sqlparse is a non-validating SQL parser module for Python. Prior to 0.6.0, TokenList construction and string conversion in sqlparse/sql.py repeatedly flatten nested token subtrees constructed by groupparenthesis and groupcase, causing quadratic CPU consumption through sqlparse.parse,...

CVE-2026-54284

sqlparse versions before 0.6.0 have a CPU DoS flaw: TokenList.__init__ calls str(self), which recursively flattens the entire subtree on every group construction, producing O(n*d) cost. A ~2 KB deeply-nested SQL payload pins a worker for ~10 seconds (~5000x amplification). Flask-based SQL formatt...