Out-of-bounds data disclosure via signed-char table index
Published Jul 16, 2026 · Updated Jul 16, 2026
Out-of-bounds read in YAML::Syck before 1.47 allows attackers to expose process memory through crafted !!binary YAML input. In bundled libsyck's syck_base64dec, each raw byte indexes b64_xtable as a signed char, so bytes at or above 0x80 become negative indexes that read before the table. The default Load and LoadFile paths reach the decoder without special flags when an untrusted document contains a !!binary scalar, and read values can enter the decoded result.
Summary
What happened
Out-of-bounds read in YAML::Syck before 1.47 allows attackers to expose process memory through crafted !!binary YAML input. In bundled libsyck's syck_base64dec, each raw byte indexes b64_xtable as a signed char, so bytes at or above 0x80 become negative indexes that read before the table. The default Load and LoadFile paths reach the decoder without special flags when an untrusted document contains a !!binary scalar, and read values can enter the decoded result.
The record
- CVE
- CVE-2026-57075
- Published
- Jul 16, 2026
- Updated
- Jul 16, 2026
- Vendor
- Todd Rinaldo
- Product
- YAML::Syck
- Classifications
- CWE-125, T1005
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jul 16, 2026CVE publishedPublication date reported by the CVE source.
- Jul 16, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=0 <1.47
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Public exploit references
- CVE-2026-57075 base64 out-of-bounds read regression testproof of concept · validated
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Technologies
Your stack
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Your stack
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