CVE-2026-109449 Symfony: Unbounded Nesting in the Expression Parser Lets Untrusted Expressions Crash the Process

In Symfony Expression Language versions prior to 5.4.54, 6.4.48, 7.4.21, and 8.1.9, the parser of the ExpressionLanguage component built its node tree with no bound on its depth. An expression made of tens of thousands of nested unary operators, array literals, binary operators or property access...