CVE-2026-57077

Description

YAML::Syck versions before 1.47 for Perl allow an out-of-bounds read via an unbounded newline scan in newline_len. In the bundled libsyck newline_len and is_newline dereference the scan pointer, and the following byte for a "\r\n" pair, with no NUL-terminator or bounds check. During block-scalar lexing at a document boundary the scan runs one byte past the heap lexer buffer. This is an incomplete fix of CVE-2025-11683, on a lexer path the earlier fix did not cover. Any caller that runs Load or LoadFile on an untrusted document with a block scalar at a document boundary reaches the over-read.

Weaknesses

• CWE-125 — CWE-125 Out-of-bounds Read

Affected products

References

• https://metacpan.org/release/TODDR/YAML-Syck-1.47/changes (release-notes)
• https://github.com/toddr/YAML-Syck/commit/44c90a109ec3215ee7ce747bd11209835e123d8b.patch (patch)
• https://www.cve.org/CVERecord?id=CVE-2025-11683 (related)