UBUNTU-CVE-2026-19487

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Source
https://ubuntu.com/security/CVE-2026-19487
Import Source
https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-19487.json
JSON Data
https://api.osv.dev/v1/vulns/UBUNTU-CVE-2026-19487
Upstream
Downstream
Related
Published
2026-08-13T16:17:00Z
Modified
2026-09-09T00:30:31Z
Severity
  • 5.3 (Medium) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L CVSS Calculator
  • Ubuntu - medium
Summary
[none]
Details

Perl versions from 5.9.4 before 5.41.9 produce incorrect regular expression match results when a stale failure flag ends the Aho-Corasick prescan early in S_find_byclass. The prescan walks the subject for positions where the full pattern could match, and the engine tries it from the leftmost one recorded. A failing transition sets the failed flag, and a later successful transition does not clear it, so the prescan reads the stale flag as a failure and stops before it can record a candidate that starts earlier. It takes a subject where one candidate is recorded and a later character then forces a fallback through a fail link that succeeds. Example: "ABCDE" =~ m/ABCF|BCDE|C/; # matches C at offset 2, not BCDE "ABCDE" =~ m/ABCF|BCDE|C(G)/; # no match, BCDE missed An alternation like this can miss input it should match, or match it on the wrong branch, so an access or filtering decision made from the result can be wrong.

References

Affected packages

Ubuntu:22.04:LTS
perl

Package

Name
perl
Purl
pkg:deb/ubuntu/perl?arch=source&distro=jammy

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected
Fixed
5.34.0-3ubuntu1.9

Affected versions

5.*
5.32.1-3ubuntu3
5.34.0-3ubuntu1
5.34.0-3ubuntu1.1
5.34.0-3ubuntu1.2
5.34.0-3ubuntu1.3
5.34.0-3ubuntu1.4
5.34.0-3ubuntu1.5
5.34.0-3ubuntu1.7
5.34.0-3ubuntu1.8

Ecosystem specific 

{
    "availability": "No subscription required",
    "binaries": [
        {
            "binary_name": "libperl5.34",
            "binary_version": "5.34.0-3ubuntu1.9"
        },
        {
            "binary_name": "perl",
            "binary_version": "5.34.0-3ubuntu1.9"
        },
        {
            "binary_name": "perl-base",
            "binary_version": "5.34.0-3ubuntu1.9"
        },
        {
            "binary_name": "perl-debug",
            "binary_version": "5.34.0-3ubuntu1.9"
        },
        {
            "binary_name": "perl-modules-5.34",
            "binary_version": "5.34.0-3ubuntu1.9"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-19487.json"
Ubuntu:24.04:LTS
perl

Package

Name
perl
Purl
pkg:deb/ubuntu/perl?arch=source&distro=noble

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected

Affected versions

5.*
5.36.0-9ubuntu1
5.36.0-10ubuntu1
5.38.2-3
5.38.2-3.2
5.38.2-3.2build1
5.38.2-3.2build2
5.38.2-3.2build2.1
5.38.2-3.2ubuntu0.1
5.38.2-3.2ubuntu0.2
5.38.2-3.2ubuntu0.3
5.38.2-3.2ubuntu0.4

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "libperl5.38t64",
            "binary_version": "5.38.2-3.2ubuntu0.4"
        },
        {
            "binary_name": "perl",
            "binary_version": "5.38.2-3.2ubuntu0.4"
        },
        {
            "binary_name": "perl-base",
            "binary_version": "5.38.2-3.2ubuntu0.4"
        },
        {
            "binary_name": "perl-debug",
            "binary_version": "5.38.2-3.2ubuntu0.4"
        },
        {
            "binary_name": "perl-modules-5.38",
            "binary_version": "5.38.2-3.2ubuntu0.4"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-19487.json"
Ubuntu:26.04:LTS
perl

Package

Name
perl
Purl
pkg:deb/ubuntu/perl?arch=source&distro=resolute

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected
Fixed
5.40.1-7ubuntu0.2

Affected versions

5.*
5.40.1-6build1
5.40.1-7build1
5.40.1-7ubuntu0.1

Ecosystem specific 

{
    "availability": "No subscription required",
    "binaries": [
        {
            "binary_name": "libperl5.40",
            "binary_version": "5.40.1-7ubuntu0.2"
        },
        {
            "binary_name": "perl",
            "binary_version": "5.40.1-7ubuntu0.2"
        },
        {
            "binary_name": "perl-base",
            "binary_version": "5.40.1-7ubuntu0.2"
        },
        {
            "binary_name": "perl-debug",
            "binary_version": "5.40.1-7ubuntu0.2"
        },
        {
            "binary_name": "perl-modules-5.40",
            "binary_version": "5.40.1-7ubuntu0.2"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-19487.json"
Ubuntu:Pro:14.04:LTS
perl

Package

Name
perl
Purl
pkg:deb/ubuntu/perl?arch=source&distro=esm-infra-legacy%2Ftrusty

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected
Fixed
5.18.2-2ubuntu1.7+esm9

Affected versions

5.*
5.14.2-21build1
5.18.1-4
5.18.1-4build1
5.18.1-5
5.18.2-2
5.18.2-2ubuntu1
5.18.2-2ubuntu1.1
5.18.2-2ubuntu1.3
5.18.2-2ubuntu1.4
5.18.2-2ubuntu1.6
5.18.2-2ubuntu1.7
5.18.2-2ubuntu1.7+esm3
5.18.2-2ubuntu1.7+esm4
5.18.2-2ubuntu1.7+esm5
5.18.2-2ubuntu1.7+esm7
5.18.2-2ubuntu1.7+esm8

Ecosystem specific 

{
    "availability": "Available with Ubuntu Pro with Legacy support add-on: https://ubuntu.com/pro",
    "binaries": [
        {
            "binary_name": "libcgi-fast-perl",
            "binary_version": "5.18.2-2ubuntu1.7+esm9"
        },
        {
            "binary_name": "libperl5.18",
            "binary_version": "5.18.2-2ubuntu1.7+esm9"
        },
        {
            "binary_name": "perl",
            "binary_version": "5.18.2-2ubuntu1.7+esm9"
        },
        {
            "binary_name": "perl-base",
            "binary_version": "5.18.2-2ubuntu1.7+esm9"
        },
        {
            "binary_name": "perl-debug",
            "binary_version": "5.18.2-2ubuntu1.7+esm9"
        },
        {
            "binary_name": "perl-modules",
            "binary_version": "5.18.2-2ubuntu1.7+esm9"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-19487.json"
Ubuntu:Pro:16.04:LTS
perl

Package

Name
perl
Purl
pkg:deb/ubuntu/perl?arch=source&distro=esm-infra-legacy%2Fxenial

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected
Fixed
5.22.1-9ubuntu0.9+esm4

Affected versions

5.*
5.20.2-6
5.22.1-3
5.22.1-4
5.22.1-5
5.22.1-7
5.22.1-8
5.22.1-9
5.22.1-9ubuntu0.2
5.22.1-9ubuntu0.3
5.22.1-9ubuntu0.5
5.22.1-9ubuntu0.6
5.22.1-9ubuntu0.9
5.22.1-9ubuntu0.9+esm1
5.22.1-9ubuntu0.9+esm2
5.22.1-9ubuntu0.9+esm3

Ecosystem specific 

{
    "availability": "Available with Ubuntu Pro with Legacy support add-on: https://ubuntu.com/pro",
    "binaries": [
        {
            "binary_name": "libperl5.22",
            "binary_version": "5.22.1-9ubuntu0.9+esm4"
        },
        {
            "binary_name": "perl",
            "binary_version": "5.22.1-9ubuntu0.9+esm4"
        },
        {
            "binary_name": "perl-base",
            "binary_version": "5.22.1-9ubuntu0.9+esm4"
        },
        {
            "binary_name": "perl-debug",
            "binary_version": "5.22.1-9ubuntu0.9+esm4"
        },
        {
            "binary_name": "perl-modules-5.22",
            "binary_version": "5.22.1-9ubuntu0.9+esm4"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-19487.json"
Ubuntu:Pro:18.04:LTS
perl

Package

Name
perl
Purl
pkg:deb/ubuntu/perl?arch=source&distro=esm-infra%2Fbionic

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected
Fixed
5.26.1-6ubuntu0.7+esm4

Affected versions

5.*
5.26.0-8ubuntu1
5.26.1-2ubuntu1
5.26.1-3
5.26.1-4
5.26.1-4build1
5.26.1-5
5.26.1-6
5.26.1-6ubuntu0.1
5.26.1-6ubuntu0.2
5.26.1-6ubuntu0.3
5.26.1-6ubuntu0.5
5.26.1-6ubuntu0.6
5.26.1-6ubuntu0.7
5.26.1-6ubuntu0.7+esm2
5.26.1-6ubuntu0.7+esm3

Ecosystem specific 

{
    "availability": "Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro",
    "binaries": [
        {
            "binary_name": "libperl5.26",
            "binary_version": "5.26.1-6ubuntu0.7+esm4"
        },
        {
            "binary_name": "perl",
            "binary_version": "5.26.1-6ubuntu0.7+esm4"
        },
        {
            "binary_name": "perl-base",
            "binary_version": "5.26.1-6ubuntu0.7+esm4"
        },
        {
            "binary_name": "perl-debug",
            "binary_version": "5.26.1-6ubuntu0.7+esm4"
        },
        {
            "binary_name": "perl-modules-5.26",
            "binary_version": "5.26.1-6ubuntu0.7+esm4"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-19487.json"
Ubuntu:Pro:20.04:LTS
perl

Package

Name
perl
Purl
pkg:deb/ubuntu/perl?arch=source&distro=esm-infra%2Ffocal

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected
Fixed
5.30.0-9ubuntu0.5+esm4

Affected versions

5.*
5.28.1-6build1
5.30.0-7
5.30.0-9
5.30.0-9build1
5.30.0-9ubuntu0.2
5.30.0-9ubuntu0.3
5.30.0-9ubuntu0.4
5.30.0-9ubuntu0.5
5.30.0-9ubuntu0.5+esm2
5.30.0-9ubuntu0.5+esm3

Ecosystem specific 

{
    "availability": "Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro",
    "binaries": [
        {
            "binary_name": "libperl5.30",
            "binary_version": "5.30.0-9ubuntu0.5+esm4"
        },
        {
            "binary_name": "perl",
            "binary_version": "5.30.0-9ubuntu0.5+esm4"
        },
        {
            "binary_name": "perl-base",
            "binary_version": "5.30.0-9ubuntu0.5+esm4"
        },
        {
            "binary_name": "perl-debug",
            "binary_version": "5.30.0-9ubuntu0.5+esm4"
        },
        {
            "binary_name": "perl-modules-5.30",
            "binary_version": "5.30.0-9ubuntu0.5+esm4"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-19487.json"