CVE-2026-57075: CWE-125 Out-of-bounds Read in 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. 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.
AI Analysis
Technical Summary
CVE-2026-57075 is an out-of-bounds read vulnerability (CWE-125) in YAML::Syck versions before 1.47 for Perl. The issue arises in the syck_base64dec function of the bundled libsyck library, where a signed char is used as an index into a 256-entry static table (b64_xtable). When the base64 decoder processes !!binary YAML nodes containing bytes with the high bit set (>= 0x80), the signed char sign-extends to a negative value, causing the code to read memory before the table bounds. This vulnerability is reachable via the default Load or LoadFile functions on untrusted YAML documents containing such !!binary scalars. The out-of-bounds read may result in unexpected data being included in the decoded output.
Potential Impact
The vulnerability allows an out-of-bounds read when parsing untrusted YAML documents with !!binary scalars containing high-bit bytes. This can lead to disclosure of memory contents adjacent to the lookup table, potentially leaking sensitive information. There is no indication of code execution or denial of service from the provided data. No known exploits are reported in the wild at this time.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Users should avoid loading untrusted YAML documents with vulnerable versions of YAML::Syck. Monitor vendor channels for updates or patches addressing this issue.
CVE-2026-57075: CWE-125 Out-of-bounds Read in TODDR YAML::Syck
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.
CVSS v3.1
Score 9.1critical
Affected software
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Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-57075 is an out-of-bounds read vulnerability (CWE-125) in YAML::Syck versions before 1.47 for Perl. The issue arises in the syck_base64dec function of the bundled libsyck library, where a signed char is used as an index into a 256-entry static table (b64_xtable). When the base64 decoder processes !!binary YAML nodes containing bytes with the high bit set (>= 0x80), the signed char sign-extends to a negative value, causing the code to read memory before the table bounds. This vulnerability is reachable via the default Load or LoadFile functions on untrusted YAML documents containing such !!binary scalars. The out-of-bounds read may result in unexpected data being included in the decoded output.
Potential Impact
The vulnerability allows an out-of-bounds read when parsing untrusted YAML documents with !!binary scalars containing high-bit bytes. This can lead to disclosure of memory contents adjacent to the lookup table, potentially leaking sensitive information. There is no indication of code execution or denial of service from the provided data. No known exploits are reported in the wild at this time.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Users should avoid loading untrusted YAML documents with vulnerable versions of YAML::Syck. Monitor vendor channels for updates or patches addressing this issue.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- CPANSec
- Date Reserved
- 2026-06-23T18:02:32.994Z
- Cvss Version
- null
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6a59a5f668715ace43451fc8
Added to database: 07/17/2026, 03:48:06 UTC
Last enriched: 07/17/2026, 04:02:50 UTC
Last updated: 08/28/2026, 22:52:12 UTC
Views: 68
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