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Medium ALAS2-2026-3997 2 CVEs

Moderate: perl security update (Amazon Linux 2)

Published Oct 12, 2026 · Updated Oct 12, 2026

Summary

Package updates are available for Amazon Linux 2 that fix the following vulnerabilities: CVE-2026-57432: Perl versions through 5.43.10 have an integer overflow in S_measure_struct leading to an out-of-bounds heap read in pack and unpack. S_measure_struct adds each item's size times its repeat count to a running total with no overflow check, so a large repeat count in a pack or unpack template wraps the signed SSize_t total negative. The @, X, and x position codes then guard their moves with a signed length comparison that passes when the length is negative, advancing the buffer pointer out of bounds. A template derived from untrusted input can read heap memory past the buffer and return it to the caller. CVE-2026-13221: Perl versions through 5.43.9 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.

Fixed packages 19

ReleasePackageFixed in
Amazon Linux · 2 perl 4:5.16.3-299.amzn2.0.5
Amazon Linux · 2 perl-core 0:5.16.3-299.amzn2.0.5
Amazon Linux · 2 perl-CPAN 0:1.9800-299.amzn2.0.5
Amazon Linux · 2 perl-debuginfo 4:5.16.3-299.amzn2.0.5
Amazon Linux · 2 perl-devel 4:5.16.3-299.amzn2.0.5
Amazon Linux · 2 perl-ExtUtils-CBuilder 1:0.28.2.6-299.amzn2.0.5
Amazon Linux · 2 perl-ExtUtils-Embed 0:1.30-299.amzn2.0.5
Amazon Linux · 2 perl-ExtUtils-Install 0:1.58-299.amzn2.0.5
Amazon Linux · 2 perl-IO-Zlib 1:1.10-299.amzn2.0.5
Amazon Linux · 2 perl-libs 4:5.16.3-299.amzn2.0.5
Amazon Linux · 2 perl-Locale-Maketext-Simple 1:0.21-299.amzn2.0.5
Amazon Linux · 2 perl-macros 4:5.16.3-299.amzn2.0.5
Amazon Linux · 2 perl-Module-CoreList 1:2.76.02-299.amzn2.0.5
Amazon Linux · 2 perl-Module-Loaded 1:0.08-299.amzn2.0.5
Amazon Linux · 2 perl-Object-Accessor 1:0.42-299.amzn2.0.5
Amazon Linux · 2 perl-Package-Constants 1:0.02-299.amzn2.0.5
Amazon Linux · 2 perl-Pod-Escapes 1:1.04-299.amzn2.0.5
Amazon Linux · 2 perl-tests 4:5.16.3-299.amzn2.0.5
Amazon Linux · 2 perl-Time-Piece 0:1.20.1-299.amzn2.0.5

Vulnerabilities 2

  • Critical 9.1

    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

    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 suc…

  • High 8.4

    Perl versions before 5.40.5-RC1, from 5.41.0 before 5.42.3-RC1, from 5.43.0 before 5.43.11 have an integer overflow in S_measure_struct leading to an out-of-bounds heap read in pack and unpack

    Perl versions before 5.40.5-RC1, from 5.41.0 before 5.42.3-RC1, from 5.43.0 before 5.43.11 have an integer overflow in S_measure_struct leading to an out-of-bounds heap read in pack and unpack. S_measure_struct adds each item's size times its repeat count to …

References

  • web
    https://alas.aws.amazon.com/cve/html/CVE-2026-13221.html
  • web
    https://alas.aws.amazon.com/cve/html/CVE-2026-57432.html