A vulnerability categorized as critical has been discovered in antlr ANTLR4 up to 4.13.2 . Affected is an unknown function of the file tool/src/org/antlr/v4/codegen/model/OutputFile.java of the component Grammar Action Block Handler . Executing a manipulation can lead to code injection. The identification of this vulnerability is CVE-2026-13500 . The attack may be launched remotely. Furthermore, there is an exploit available. The vendor was contacted early about this disclosure but did not respo