CVE-2026-13221

Perl versions through 5.43.9 produce silently incorrect regular expression matches when an alternation of more than 65535 fixed string branches is compiled into a trie in Perlstudychunk. When such branches are combined into a trie, the delta between the first branch and the shared tail is stored ...

CVE-2026-13221

CVE-2026-13221 affects Perl versions through 5.43.9. When an alternation of more than 65,535 fixed-string branches is compiled into a trie in Perl_study_chunk, the 16‑bit delta between the first branch and the shared tail overflows. The trie’s match decision table is truncated with no warning, pr...