CVE-2026-57075

NameCVE-2026-57075
DescriptionYAML::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.
SourceCVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)
Debian Bugs1142267

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
libyaml-syck-perl (PTS)bullseye1.34-1vulnerable
bullseye (security)1.34-1+deb11u1vulnerable
bookworm, bookworm (security)1.34-2+deb12u2vulnerable
trixie (security), trixie1.34-2+deb13u2vulnerable
forky1.36-3vulnerable
sid1.47-1vulnerable

The information below is based on the following data on fixed versions.

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
libyaml-syck-perlsource(unstable)(unfixed)1142267

Notes

https://www.openwall.com/lists/oss-security/2026/07/17/2
Fixed by: https://github.com/toddr/YAML-Syck/commit/44c90a109ec3215ee7ce747bd11209835e123d8b (1.47)

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