CVE-2026-13221 Affecting perl-base package, versions <5.42.0-160000.3.1


Severity

Recommended
0.0
high
0
10

Based on SUSE Linux Enterprise Server security rating.

Threat Intelligence

EPSS
0.49% (43rd percentile)

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  • Snyk IDSNYK-SLES1600-PERLBASE-18344382
  • published28 Jul 2026
  • disclosed22 Jul 2026

Introduced: 22 Jul 2026

CVE-2026-13221  (opens in a new tab)

How to fix?

Upgrade SLES:16.0.0 perl-base to version 5.42.0-160000.3.1 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream perl-base package and not the perl-base package as distributed by SLES. See How to fix? for SLES:16.0.0 relevant fixed versions and status.

Perl versions before 5.40.5-RC1, from 5.41.0 before 5.42.3-RC1, from 5.43.0 before 5.43.10 produce silently incorrect regular expression matches when an alternation of more than 65535 fixed string branches is compiled into a trie in Perl_study_chunk.

When such branches are combined into a trie, the delta between the first branch and the shared tail is stored in a 16-bit field. A branch count above 65535 overflows the field, and the trie's match decision table is truncated with no warning or error.

A pattern of this shape produces false positive matches (matching strings it should not) and false negative matches (failing to match strings it should). When such a pattern gates an access or filtering decision, the result is wrong.

CVSS Base Scores

version 3.1