CVE-2026-13221

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Source
https://cve.org/CVERecord?id=CVE-2026-13221
Import Source
https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-13221.json
JSON Data
https://api.osv.dev/v1/vulns/CVE-2026-13221
Downstream
Related
Published
2026-07-13T15:40:11.035Z
Modified
2026-07-29T18:30:06.952223946Z
Severity
  • 9.1 (Critical) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H CVSS Calculator
Summary
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
Details

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 Perlstudychunk.

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.

Database specific 
{
    "cwe_ids": [
        "CWE-190"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/13xxx/CVE-2026-13221.json",
    "cna_assigner": "CPANSec"
}
References

Affected packages

Git / github.com/perl/perl5

Affected ranges

Type
GIT
Repo
https://github.com/perl/perl5
Events
Introduced
0 Unknown introduced commit / All previous commits are affected
Fixed
03f74bbbd3a68350d926ee93d56ee4808c28c4c7
Database specific 
{
    "cpe": "cpe:2.3:a:perl:perl:*:*:*:*:*:*:*:*",
    "source": [
        "CPE_RANGE",
        "REFERENCES"
    ],
    "extracted_events": [
        {
            "introduced": "0"
        },
        {
            "last_affected": "5.43.9"
        }
    ]
}

Affected versions

Other
GitLive-blead
perl-5a2
perl-5a9
if-0.*
if-0.0603
if-0.0604
if-0.0605
perl-1.*
perl-1.0
perl-2.*
perl-2.0
perl-3.*
perl-3.000
perl-3.044
perl-4.*
perl-4.0.00
perl-4.0.36
perl-5.*
perl-5.000
perl-5.000o
perl-5.001
perl-5.001n
perl-5.002
perl-5.002_01
perl-5.003
perl-5.005
perl-5.6.0
perl-5.7.0
perl-5.7.1
perl-5.7.2
perl-5.7.3
perl-5.8.0
perl-5.9.0
perl-5.9.1
perl-5.9.2
perl-5.9.3
perl-5.9.4
perl-5.9.5
v5.*
v5.10.0
v5.11.0
v5.11.1
v5.11.3
v5.11.4
v5.11.5
v5.12.0
v5.12.0-RC0
v5.12.0-RC1
v5.12.0-RC2
v5.12.0-RC3
v5.12.0-RC4
v5.12.0-RC5
v5.13.0
v5.13.1
v5.13.10
v5.13.11
v5.13.2
v5.13.3
v5.13.4
v5.13.5
v5.13.6
v5.13.7
v5.13.8
v5.13.9
v5.14.0
v5.14.0-RC1
v5.14.0-RC2
v5.14.0-RC3
v5.15.0
v5.15.1
v5.15.2
v5.15.3
v5.15.4
v5.15.5
v5.15.9
v5.16.0
v5.16.0-RC1
v5.16.0-RC2
v5.17.0
v5.17.2
v5.17.4
v5.17.6
v5.17.7
v5.17.7.0
v5.17.8
v5.17.9
v5.18.0
v5.18.0-RC1
v5.18.0-RC2
v5.18.0-RC3
v5.18.0-RC4
v5.19.0
v5.19.1
v5.19.11
v5.19.2
v5.19.3
v5.19.5
v5.19.7
v5.20.0
v5.20.0-RC1
v5.21.0
v5.21.1
v5.21.10
v5.21.11
v5.21.4
v5.21.5
v5.21.6
v5.21.8
v5.21.9
v5.22.0
v5.22.0-RC1
v5.22.0-RC2
v5.23.0
v5.23.1
v5.23.2
v5.23.3
v5.23.4
v5.23.6
v5.23.7
v5.24.0
v5.24.0-RC1
v5.24.0-RC2
v5.24.0-RC3
v5.24.0-RC4
v5.24.0-RC5
v5.25.0
v5.25.11
v5.25.2
v5.25.3
v5.25.4
v5.25.5
v5.25.7
v5.25.9
v5.26.0
v5.26.0-RC2
v5.27.0
v5.27.10
v5.27.11
v5.27.3
v5.27.5
v5.27.6
v5.27.7
v5.27.8
v5.28.0
v5.28.0-RC1
v5.28.0-RC2
v5.28.0-RC3
v5.28.0-RC4
v5.29.0
v5.29.1
v5.29.10
v5.29.5
v5.29.6
v5.29.7
v5.29.8
v5.29.9
v5.30.0
v5.30.0-RC1
v5.30.0-RC2
v5.31.0
v5.31.1
v5.31.11
v5.31.2
v5.31.3
v5.31.4
v5.31.5
v5.31.7
v5.32.0
v5.32.0-RC1
v5.33.0
v5.33.1
v5.33.2
v5.33.3
v5.33.4
v5.33.7
v5.33.8
v5.33.9
v5.34.0
v5.34.0-RC1
v5.34.0-RC2
v5.35.0
v5.35.10
v5.35.11
v5.35.3
v5.35.5
v5.35.6
v5.35.8
v5.35.9
v5.36.0
v5.36.0-RC3
v5.37.0
v5.37.1
v5.37.10
v5.37.11
v5.37.2
v5.37.3
v5.37.4
v5.37.5
v5.37.6
v5.37.7
v5.37.9
v5.38.0
v5.38.0-RC1
v5.38.0-RC2
v5.39.0
v5.39.1
v5.39.3
v5.39.4
v5.39.5
v5.39.7
v5.39.8
v5.40.0
v5.40.0-RC1
v5.40.0-RC2
v5.41.0
v5.41.1
v5.41.10
v5.41.11
v5.41.12
v5.41.13
v5.41.2
v5.41.3
v5.41.4
v5.41.5
v5.41.7
v5.41.8
v5.41.9
v5.42.0
v5.42.0-RC1
v5.42.0-RC2
v5.42.0-RC3
v5.43.0
v5.43.1
v5.43.2
v5.43.6
v5.43.8
v5.43.9

Database specific

vanir_signatures_modified 
"2026-07-22T03:50:37Z"
vanir_signatures 
[
    {
        "signature_type": "Line",
        "id": "CVE-2026-13221-64dd3400",
        "deprecated": false,
        "source": "https://github.com/perl/perl5/commit/03f74bbbd3a68350d926ee93d56ee4808c28c4c7",
        "signature_version": "v1",
        "target": {
            "file": "regcomp_study.c"
        },
        "digest": {
            "line_hashes": [
                "134675665719538900810772585221767670192",
                "162168684666736337369435135427539826229",
                "144872332641364083640948895312468990898"
            ],
            "threshold": 0.9
        }
    },
    {
        "signature_type": "Function",
        "source": "https://github.com/perl/perl5/commit/03f74bbbd3a68350d926ee93d56ee4808c28c4c7",
        "deprecated": false,
        "target": {
            "file": "regcomp_study.c",
            "function": "Perl_study_chunk"
        },
        "id": "CVE-2026-13221-945874b1",
        "signature_version": "v1",
        "digest": {
            "function_hash": "236057087489884812036731213027052221607",
            "length": 42988.0
        }
    }
]
source 
"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-13221.json"