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CVE-2026-57077 is a one-byte out-of-bounds read in the bundled libsyck lexer used by YAML::Syck for Perl before version 1.47. The newline_len() and is_newline() routines dereference the scan pointer without establishing that it remains within the lexer buffer, and also dereference the next byte when checking for a carriage-return/line-feed sequence. During block-scalar lexing at a YAML document boundary, this unbounded scan can read past the heap lexer buffer. The issue is an incomplete follow-on fix for CVE-2025-11683 affecting a lexer path not covered by the earlier remediation.
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A vulnerability affecting the FreeBSD p5-yaml-syck (YAML-Syck) package. The supplied content does not describe the specific flaw.
A YAML::Syck/libsyck out-of-bounds read during block-scalar lexing at a document boundary. The newline scan can read beyond the heap lexer buffer when Load or LoadFile parses an untrusted document containing a block scalar at that boundary.
A one-byte out-of-bounds read in libsyck's lexer newline scan during block-scalar parsing, reachable via default YAML::Syck::Load() on untrusted input; described as an incomplete-fix follow-on to CVE-2025-11683.
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Cross-references every affected SKU, including bundled OEM variants.
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