CVE-2026-13221 Affecting perl:5.32/perl-perlfaq package, versions <0:5.20210520-1.module_el8.6.0+2766+8bf0b7ce


Severity

Recommended
medium

Based on AlmaLinux security rating.

Threat Intelligence

EPSS
0.53% (45th percentile)

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  • Snyk IDSNYK-ALMALINUX8-PERL-19852232
  • published16 Sept 2026
  • disclosed14 Sept 2026

Introduced: 14 Sep 2026

CVE-2026-13221  (opens in a new tab)

How to fix?

Upgrade AlmaLinux:8 perl:5.32/perl-perlfaq to version 0:5.20210520-1.module_el8.6.0+2766+8bf0b7ce or higher.
This issue was patched in ALSA-2026:67278.

NVD Description

Note: Versions mentioned in the description apply only to the upstream perl:5.32/perl-perlfaq package and not the perl:5.32/perl-perlfaq package as distributed by AlmaLinux. See How to fix? for AlmaLinux:8 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