Threats Tagged 'cve-2026-57075'

This security update for perl-YAML-Syck addresses multiple memory-safety vulnerabilities in the libsyck library that are exploitable via the default YAML::Syck::Load() function when processing untrusted input. The fixed issues include out-of-bounds reads and use-after-free conditions that could lead to crashes or potentially other impacts. The update also hardens base64 decoding and enforces maximum depth limits to prevent stack exhaustion from deeply nested inputs.

YAML::Syck versions prior to 1.47 for Perl contain a use-after-free and double-free vulnerability triggered by redefinition or removal of anchor nodes during YAML parsing. This flaw causes the interpreter to crash, resulting in a denial of service when processing untrusted documents that redefine anchors mid-parse.

YAML::Syck versions before 1.47 for Perl allow an out-of-bounds read via a signed-char lookup-table index in syck_base64dec. The base64 decoder in the bundled libsyck indexes the 256-entry static table b64_xtable with a signed char, so any !!binary byte >= 0x80 sign-extends to a negative index and reads before the table. The decoder receives the raw bytes of any !!binary node, a standard YAML type not gated by $LoadBlessed or $LoadCode, so it is reached on the default Load path. Any caller that runs Load or LoadFile on an untrusted document containing a !!binary scalar with a high-bit byte triggers the read, and the value read can surface in the decoded result.