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CVE-2026-57075 CPAN Security Group
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CVE ID: CVE-2026-57075
Distribution: YAML-Syck
Versions: before 1.47
MetaCPAN: https://metacpan.org/dist/YAML-Syck
VCS Repo: https://github.com/toddr/YAML-Syck
YAML::Syck versions before 1.47 for Perl allow an out-of-bounds read
via a signed-char lookup-table index in syck_base64dec
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.
Problem types
-------------
- CWE-125 Out-of-bounds Read
Solutions
---------
Upgrade to YAML-Syck 1.47 or later.
References
----------
https://metacpan.org/release/TODDR/YAML-Syck-1.47/changes
https://github.com/toddr/YAML-Syck/commit/44c90a109ec3215ee7ce747bd11209835e123d8b.patch
--
Paul Johnson - [email protected]
