CVE-2026-57075

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 v3 9.1 CRITICAL

9.1^/10

CVSS v3 : CRITICAL

Vector :

Exploitability : 3.9 / Impact : 5.2

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact HIGH

Integrity Impact NONE

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
https://github.com/toddr/YAML-Syck/commit/44c90a109ec3215ee7ce747bd11209835e123d8b.patch
https://metacpan.org/release/TODDR/YAML-Syck-1.47/changes
http://www.openwall.com/lists/oss-security/2026/07/17/2

Configurations

No configuration.

History

No history.

Information

Published : 2026-07-16 22:17

Updated : 2026-07-17 15:07

NVD link : CVE-2026-57075

Mitre link : CVE-2026-57075

CVE.ORG link : CVE-2026-57075

JSON object : View

Products Affected

No product.

CWE

CWE-125

Out-of-bounds Read

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