Vulnerability Description
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.
CVSS Score
CRITICAL
Related Weaknesses (CWE)
References
- https://github.com/toddr/YAML-Syck/commit/44c90a109ec3215ee7ce747bd11209835e123d
- https://metacpan.org/release/TODDR/YAML-Syck-1.47/changes
- http://www.openwall.com/lists/oss-security/2026/07/17/2
FAQ
What is CVE-2026-57075?
CVE-2026-57075 is a vulnerability with a CVSS score of 9.1 (CRITICAL). 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 tab...
How severe is CVE-2026-57075?
CVE-2026-57075 has been rated CRITICAL with a CVSS base score of 9.1/10. This is considered a critical vulnerability requiring immediate attention.
Is there a patch for CVE-2026-57075?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.