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...

CVE-2026-13221

Perl versions before 5.40.5-RC1, from 5.41.0 before 5.42.3-RC1, from 5.43.0 before 5.43.10 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...