DEBIAN-CVE-2026-13221
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.
DEBIAN-CVE-2026-13221
Primary source · Revision 1
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: osv:DEBIAN-CVE-2026-13221
perl
Source reference: /affected/0/package/name
- Affected versions
- 5.36.0-7
Source reference:
/affected/0/versions5.36.0-7+deb12u1Source reference:
/affected/0/versions5.36.0-7+deb12u2Source reference:
/affected/0/versions5.36.0-7+deb12u3Source reference:
/affected/0/versions - Fixed versions
- 5.36.0-7+deb12u4
Source reference:
/affected/0/ranges - Prerequisites
- Not stated in this record
perl
Source reference: /affected/1/package/name
- Affected versions
- 5.40.1-6
Source reference:
/affected/1/versions - Fixed versions
- 5.40.1-6+deb13u1
Source reference:
/affected/1/ranges - Prerequisites
- Not stated in this record
perl
Source reference: /affected/2/package/name
- Affected versions
- 5.40.1-6
Source reference:
/affected/2/versions5.40.1-7Source reference:
/affected/2/versions5.40.1-8Source reference:
/affected/2/versions5.42.0-1Source reference:
/affected/2/versions5.42.0-2Source reference:
/affected/2/versions5.42.0-3Source reference:
/affected/2/versions5.42.2-1Source reference:
/affected/2/versions5.42.2-2Source reference:
/affected/2/versions5.42.2-3Source reference:
/affected/2/versions - Fixed versions
- 5.42.3-1
Source reference:
/affected/2/ranges - Prerequisites
- Not stated in this record
Structured affected-version data
Original package identities and version rules from this source.
[
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "5.36.0-7+deb12u4"
}
]
}
],
"package": {
"name": "perl",
"purl": "pkg:deb/debian/perl?arch=source&distro=bookworm",
"ecosystem": "Debian:12"
},
"versions": [
"5.36.0-7",
"5.36.0-7+deb12u1",
"5.36.0-7+deb12u2",
"5.36.0-7+deb12u3"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-13221.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "5.40.1-6+deb13u1"
}
]
}
],
"package": {
"name": "perl",
"purl": "pkg:deb/debian/perl?arch=source&distro=trixie",
"ecosystem": "Debian:13"
},
"versions": [
"5.40.1-6"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-13221.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "5.42.3-1"
}
]
}
],
"package": {
"name": "perl",
"purl": "pkg:deb/debian/perl?arch=source&distro=forky",
"ecosystem": "Debian:14"
},
"versions": [
"5.40.1-6",
"5.40.1-7",
"5.40.1-8",
"5.42.0-1",
"5.42.0-2",
"5.42.0-3",
"5.42.2-1",
"5.42.2-2",
"5.42.2-3"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-13221.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
}
]- Related CVEs
- CVE-2026-13221
Source reference:
/upstream
Publisher severity
critical
Source reference: /severity/0/score
- Event
- #83708 · Revision 1
- Added to Heist Feed
- Publisher date