CVE-2026-5089 Affecting libyaml-syck-perl package, versions <1.34-2+deb13u3


Severity

Recommended
low

Based on default assessment until relevant scores are available.

Threat Intelligence

EPSS
0.33% (25th percentile)

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  • Snyk IDSNYK-DEBIAN13-LIBYAMLSYCKPERL-16726398
  • published17 May 2026
  • disclosed12 May 2026

Introduced: 12 May 2026

CVE-2026-5089  (opens in a new tab)

How to fix?

Upgrade Debian:13 libyaml-syck-perl to version 1.34-2+deb13u3 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream libyaml-syck-perl package and not the libyaml-syck-perl package as distributed by Debian. See How to fix? for Debian:13 relevant fixed versions and status.

YAML::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 &gt;= ptr &amp;&amp; *colon != &#39;:&#39; )
{
    colon--;
}
if ( *colon == &#39;:&#39; ) *colon = &#39;\0&#39;;  // 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.

CVSS Base Scores

version 3.1