YAML::Syck versions before 1.38 for Perl has an out-of-bounds read

MITRE NVD CVE.ORG JSON API Print: PDF PDF

Summary

CVECVE-2026-5089
StatePUBLISHED
AssignerCPANSec
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-05-12 17:16:21 UTC
Updated2026-05-14 15:16:49 UTC
DescriptionYAML::Syck versions before 1.38 for Perl has an out-of-bounds read. The base60 (sexagesimal) parsing code in perl_syck.h has a buffer underflow bug in both int#base60 and float#base60 handlers. When processing the leftmost segment of a colon-separated value (e.g., the 1 in 1:30:45), the inner while loop can decrement a pointer past the start of the string buffer: while ( colon >= ptr && *colon != ':' ) { colon--; } if ( *colon == ':' ) *colon = '\0'; // colon may be ptr-1 here When no colon is found (final/leftmost segment), colon becomes ptr-1, and the subsequent *colon dereference reads one byte before the allocated buffer.

Risk And Classification

Primary CVSS: v3.1 7.3 HIGH from ADP

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L

EPSS: 0.000460000 probability, percentile 0.144630000 (date 2026-05-25)

Problem Types: CWE-124 | CWE-124 CWE-124 Buffer Underwrite ('Buffer Underflow')

VersionSourceTypeScoreSeverityVector
3.1ADPDECLARED7.3HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
3.1134c704f-9b21-4f2e-91b3-4a467353bcc0Secondary7.3HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
Low
Availability
Low

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA TODDR YAMLSyck affected 1.38 custom Not specified

References

ReferenceSourceLinkTags
github.com/cpan-authors/YAML-Syck/pull/133 9b29abf9-4ab0-4765-b253-1875cd9b441e github.com
metacpan.org/release/TODDR/YAML-Syck-1.38/changes 9b29abf9-4ab0-4765-b253-1875cd9b441e metacpan.org
github.com/cpan-authors/YAML-Syck/commit/208a4d3bd1b5cdb4a791a6e3905bd6b... 9b29abf9-4ab0-4765-b253-1875cd9b441e github.com
github.com/cpan-authors/YAML-Syck/issues/132 134c704f-9b21-4f2e-91b3-4a467353bcc0 github.com
www.openwall.com/lists/oss-security/2026/05/12/16 af854a3a-2127-422b-91ae-364da2661108 www.openwall.com
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Additional Advisory Data

Solutions

CNA: Upgrade to YAML::Syck version 1.38 or later.

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