CVE-2026-45305 Symfony: YAML Parser ReDoS via Catastrophic Backtracking in Parser::cleanup() Regex

Symfony is a PHP framework for web and console applications and a set of reusable PHP components. Prior to 5.4.52, 6.4.40, 7.4.12, and 8.0.12, Symfony\Component\Yaml\Parser::cleanup used regular expressions with overlapping quantifiers for YAML directive, comment, and document marker cleanup,...