CVE-2026-57075 YAML::Syck versions before 1.47 for Perl allow an out-of-bounds read via a signed-char lookup-table index in syck_base64dec

YAML::Syck versions before 1.47 for Perl allow an out-of-bounds read via a signed-char lookup-table index in syckbase64dec. The base64 decoder in the bundled libsyck indexes the 256-entry static table b64xtable with a signed char, so any !!binary byte = 0x80 sign-extends to a negative index and...