CVE catalog

CVE-2026-13221

Severity: Critical · CVSS 9.1CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H
Published: Jul 13, 2026, 5:16:00 PM UTC
Source: [NVD] · [CVE record]
EPSS: 0.43% · Oct 23, 2026

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.

Vulnerable and fixed packages

Distribution-reported package versions and fixes. These do not depend on matching against the OpenFactory package catalog.

Distribution	Package	Release	Version	Status
Debian	perl	sid	`5.42.3-1`	fixed
Debian	perl	forky	`5.42.3-1`	fixed
Debian	perl	trixie	`5.40.1-6+deb13u1`	fixed
Debian	perl	bookworm	`5.36.0-7+deb12u3`	vulnerable
Debian	perl	bookworm-security	`5.36.0-7+deb12u4`	fixed
Cpe	perl	Not reported	Not reported	vulnerable
Ubuntu	perl	noble	`5.38.2-3.2ubuntu0.4`	fixed
Ubuntu	libperl-dev	noble	`5.38.2-3.2ubuntu0.4`	fixed
Ubuntu	libperl5.38t64	noble	`5.38.2-3.2ubuntu0.4`	fixed
Ubuntu	perl-base	noble	`5.38.2-3.2ubuntu0.4`	fixed
Ubuntu	perl-debug	noble	`5.38.2-3.2ubuntu0.4`	fixed
Ubuntu	perl-doc	noble	`5.38.2-3.2ubuntu0.4`	fixed
Ubuntu	perl-modules-5.38	noble	`5.38.2-3.2ubuntu0.4`	fixed
Cpe	perl	Not reported	Not reported	unknown
Alpine	perl	3.24	`5.42.2-r1`	fixed
Ubuntu	perl	pro	`5.28.1-6build1`	vulnerable
Ubuntu	perl	pro	`5.30.0-7`	vulnerable
Ubuntu	perl	pro	`5.30.0-9`	vulnerable
Ubuntu	perl	pro	`5.30.0-9build1`	vulnerable
Ubuntu	perl	pro	`5.30.0-9ubuntu0.2`	vulnerable
Ubuntu	perl	pro	`5.30.0-9ubuntu0.3`	vulnerable
Ubuntu	perl	pro	`5.30.0-9ubuntu0.4`	vulnerable
Ubuntu	perl	pro	`5.30.0-9ubuntu0.5`	vulnerable
Ubuntu	perl	pro	`5.30.0-9ubuntu0.5+esm2`	vulnerable
Ubuntu	perl	pro	`5.30.0-9ubuntu0.5+esm3`	fixed
Ubuntu	perl	22.04	`5.32.1-3ubuntu3`	vulnerable
Ubuntu	perl	22.04	`5.34.0-3ubuntu1`	vulnerable
Ubuntu	perl	22.04	`5.34.0-3ubuntu1.1`	vulnerable
Ubuntu	perl	22.04	`5.34.0-3ubuntu1.2`	vulnerable
Ubuntu	perl	22.04	`5.34.0-3ubuntu1.3`	vulnerable
Ubuntu	perl	22.04	`5.34.0-3ubuntu1.4`	vulnerable
Ubuntu	perl	22.04	`5.34.0-3ubuntu1.5`	vulnerable
Ubuntu	perl	22.04	`5.34.0-3ubuntu1.7`	vulnerable
Ubuntu	perl	22.04	`5.34.0-3ubuntu1.8`	fixed
Ubuntu	perl	24.04	`5.36.0-9ubuntu1`	vulnerable
Ubuntu	perl	24.04	`5.36.0-10ubuntu1`	vulnerable
Ubuntu	perl	24.04	`5.38.2-3`	vulnerable
Ubuntu	perl	24.04	`5.38.2-3.2`	vulnerable
Ubuntu	perl	24.04	`5.38.2-3.2build1`	vulnerable
Ubuntu	perl	24.04	`5.38.2-3.2build2`	vulnerable
Ubuntu	perl	24.04	`5.38.2-3.2build2.1`	vulnerable
Ubuntu	perl	24.04	`5.38.2-3.2ubuntu0.1`	vulnerable
Ubuntu	perl	24.04	`5.38.2-3.2ubuntu0.2`	vulnerable
Ubuntu	perl	24.04	`5.38.2-3.2ubuntu0.3`	vulnerable
Ubuntu	perl	24.04	`5.38.2-3.2ubuntu0.4`	fixed
Ubuntu	perl	26.04	`5.40.1-6build1`	vulnerable
Ubuntu	perl	26.04	`5.40.1-7build1`	vulnerable
Ubuntu	perl	26.04	`5.40.1-7ubuntu0.1`	vulnerable
Ubuntu	perl	26.04	`5.40.1-7ubuntu0.2`	vulnerable
Ubuntu	perl	26.04	`5.40.1-7ubuntu0.3`	fixed

Fixed-version evidence

Distribution	Package	Type	Release	Fixed version	Urgency	Origin	Bugs
Debian	perl	source	sid	`5.42.3-1`	not yet assigned	Not reported	[1142037]
Debian	perl	source	forky	`5.42.3-1`	not yet assigned	Not reported	[1142037]
Debian	perl	source	trixie	`5.40.1-6+deb13u1`	not yet assigned	Not reported	[1142037]
Debian	perl	source	bookworm	`5.36.0-7+deb12u4`	not yet assigned	Not reported	[1142037]
Ubuntu	perl	deb	noble	`5.38.2-3.2ubuntu0.4`	Not reported	Not reported	Not reported
Ubuntu	libperl-dev	deb	noble	`5.38.2-3.2ubuntu0.4`	Not reported	Not reported	Not reported
Ubuntu	libperl5.38t64	deb	noble	`5.38.2-3.2ubuntu0.4`	Not reported	Not reported	Not reported
Ubuntu	perl-base	deb	noble	`5.38.2-3.2ubuntu0.4`	Not reported	Not reported	Not reported
Ubuntu	perl-debug	deb	noble	`5.38.2-3.2ubuntu0.4`	Not reported	Not reported	Not reported
Ubuntu	perl-doc	deb	noble	`5.38.2-3.2ubuntu0.4`	Not reported	Not reported	Not reported
Ubuntu	perl-modules-5.38	deb	noble	`5.38.2-3.2ubuntu0.4`	Not reported	Not reported	Not reported
Alpine	perl	apk	3.24	`5.42.2-r1`	Not reported	ALPINE-CVE-2026-13221	Not reported
Ubuntu	perl	deb	pro	`5.30.0-9ubuntu0.5+esm3`	Not reported	UBUNTU-CVE-2026-13221	Not reported
Ubuntu	perl	deb	22.04	`5.34.0-3ubuntu1.8`	Not reported	UBUNTU-CVE-2026-13221	Not reported
Ubuntu	perl	deb	24.04	`5.38.2-3.2ubuntu0.4`	Not reported	UBUNTU-CVE-2026-13221	Not reported
Ubuntu	perl	deb	26.04	`5.40.1-7ubuntu0.3`	Not reported	UBUNTU-CVE-2026-13221	Not reported

[Debian bug #1142037]

OpenFactory catalog packages

[Debian 12 (Bookworm)]

[libperl5.36]Affected
Source package: [perl]
Details (4)
- 5.36.0-7+deb12u3 · amd64 · bookworm
  Affected · Fixed: 5.36.0-7+deb12u4
  nvd · perl · debian · bookworm; nvd · perl · debian · 12
- 5.36.0-7+deb12u3 · arm64 · bookworm
  Affected · Fixed: 5.36.0-7+deb12u4
  nvd · perl · debian · bookworm; nvd · perl · debian · 12
- 5.36.0-7+deb12u2 · amd64 · bookworm-security
  Affected · Fixed: 5.36.0-7+deb12u4
  nvd · perl · debian · bookworm; nvd · perl · debian · 12
- 5.36.0-7+deb12u2 · arm64 · bookworm-security
  Affected · Fixed: 5.36.0-7+deb12u4
  nvd · perl · debian · bookworm; nvd · perl · debian · 12
[libperl-dev]Affected
Source package: [perl]
Details (4)
- 5.36.0-7+deb12u3 · amd64 · bookworm
  Affected · Fixed: 5.36.0-7+deb12u4
  nvd · perl · debian · bookworm; nvd · perl · debian · 12
- 5.36.0-7+deb12u3 · arm64 · bookworm
  Affected · Fixed: 5.36.0-7+deb12u4
  nvd · perl · debian · bookworm; nvd · perl · debian · 12
- 5.36.0-7+deb12u2 · amd64 · bookworm-security
  Affected · Fixed: 5.36.0-7+deb12u4
  nvd · perl · debian · bookworm; nvd · perl · debian · 12
- 5.36.0-7+deb12u2 · arm64 · bookworm-security
  Affected · Fixed: 5.36.0-7+deb12u4
  nvd · perl · debian · bookworm; nvd · perl · debian · 12
[perl]Affected
Details (4)
- 5.36.0-7+deb12u3 · amd64 · bookworm
  Affected · Fixed: 5.36.0-7+deb12u4
  nvd · perl · debian · bookworm; nvd · perl · debian · 12
- 5.36.0-7+deb12u3 · arm64 · bookworm
  Affected · Fixed: 5.36.0-7+deb12u4
  nvd · perl · debian · bookworm; nvd · perl · debian · 12
- 5.36.0-7+deb12u2 · amd64 · bookworm-security
  Affected · Fixed: 5.36.0-7+deb12u4
  nvd · perl · debian · bookworm; nvd · perl · debian · 12
- 5.36.0-7+deb12u2 · arm64 · bookworm-security
  Affected · Fixed: 5.36.0-7+deb12u4
  nvd · perl · debian · bookworm; nvd · perl · debian · 12
[perl-base]Affected
Source package: [perl]
Details (4)
- 5.36.0-7+deb12u3 · amd64 · bookworm
  Affected · Fixed: 5.36.0-7+deb12u4
  nvd · perl · debian · bookworm; nvd · perl · debian · 12
- 5.36.0-7+deb12u3 · arm64 · bookworm
  Affected · Fixed: 5.36.0-7+deb12u4
  nvd · perl · debian · bookworm; nvd · perl · debian · 12
- 5.36.0-7+deb12u2 · amd64 · bookworm-security
  Affected · Fixed: 5.36.0-7+deb12u4
  nvd · perl · debian · bookworm; nvd · perl · debian · 12
- 5.36.0-7+deb12u2 · arm64 · bookworm-security
  Affected · Fixed: 5.36.0-7+deb12u4
  nvd · perl · debian · bookworm; nvd · perl · debian · 12
[perl-debug]Affected
Source package: [perl]
Details (4)
- 5.36.0-7+deb12u3 · amd64 · bookworm
  Affected · Fixed: 5.36.0-7+deb12u4
  nvd · perl · debian · bookworm; nvd · perl · debian · 12
- 5.36.0-7+deb12u3 · arm64 · bookworm
  Affected · Fixed: 5.36.0-7+deb12u4
  nvd · perl · debian · bookworm; nvd · perl · debian · 12
- 5.36.0-7+deb12u2 · amd64 · bookworm-security
  Affected · Fixed: 5.36.0-7+deb12u4
  nvd · perl · debian · bookworm; nvd · perl · debian · 12
- 5.36.0-7+deb12u2 · arm64 · bookworm-security
  Affected · Fixed: 5.36.0-7+deb12u4
  nvd · perl · debian · bookworm; nvd · perl · debian · 12
[perl-doc]Affected
Source package: [perl]
Details (4)
- 5.36.0-7+deb12u3 · all · bookworm
  Affected · Fixed: 5.36.0-7+deb12u4
  nvd · perl · debian · bookworm; nvd · perl · debian · 12
- 5.36.0-7+deb12u3 · all · bookworm
  Affected · Fixed: 5.36.0-7+deb12u4
  nvd · perl · debian · bookworm; nvd · perl · debian · 12
- 5.36.0-7+deb12u2 · all · bookworm-security
  Affected · Fixed: 5.36.0-7+deb12u4
  nvd · perl · debian · bookworm; nvd · perl · debian · 12
- 5.36.0-7+deb12u2 · all · bookworm-security
  Affected · Fixed: 5.36.0-7+deb12u4
  nvd · perl · debian · bookworm; nvd · perl · debian · 12
[perl-modules-5.36]Affected
Source package: [perl]
Details (4)
- 5.36.0-7+deb12u3 · all · bookworm
  Affected · Fixed: 5.36.0-7+deb12u4
  nvd · perl · debian · bookworm; nvd · perl · debian · 12
- 5.36.0-7+deb12u3 · all · bookworm
  Affected · Fixed: 5.36.0-7+deb12u4
  nvd · perl · debian · bookworm; nvd · perl · debian · 12
- 5.36.0-7+deb12u2 · all · bookworm-security
  Affected · Fixed: 5.36.0-7+deb12u4
  nvd · perl · debian · bookworm; nvd · perl · debian · 12
- 5.36.0-7+deb12u2 · all · bookworm-security
  Affected · Fixed: 5.36.0-7+deb12u4
  nvd · perl · debian · bookworm; nvd · perl · debian · 12

[Debian 13 (Trixie)]

[libperl5.40]Affected
Source package: [perl]
Details (2)
- 5.40.1-6 · amd64 · trixie
  Affected · Fixed: 5.40.1-6+deb13u1
  nvd · perl · debian · 13
- 5.40.1-6 · arm64 · trixie
  Affected · Fixed: 5.40.1-6+deb13u1
  nvd · perl · debian · 13
[libperl-dev]Affected
Source package: [perl]
Details (2)
- 5.40.1-6 · amd64 · trixie
  Affected · Fixed: 5.40.1-6+deb13u1
  nvd · perl · debian · 13
- 5.40.1-6 · arm64 · trixie
  Affected · Fixed: 5.40.1-6+deb13u1
  nvd · perl · debian · 13
[perl]Affected
Details (2)
- 5.40.1-6 · amd64 · trixie
  Affected · Fixed: 5.40.1-6+deb13u1
  nvd · perl · debian · 13
- 5.40.1-6 · arm64 · trixie
  Affected · Fixed: 5.40.1-6+deb13u1
  nvd · perl · debian · 13
[perl-base]Affected
Source package: [perl]
Details (2)
- 5.40.1-6 · amd64 · trixie
  Affected · Fixed: 5.40.1-6+deb13u1
  nvd · perl · debian · 13
- 5.40.1-6 · arm64 · trixie
  Affected · Fixed: 5.40.1-6+deb13u1
  nvd · perl · debian · 13
[perl-debug]Affected
Source package: [perl]
Details (2)
- 5.40.1-6 · amd64 · trixie
  Affected · Fixed: 5.40.1-6+deb13u1
  nvd · perl · debian · 13
- 5.40.1-6 · arm64 · trixie
  Affected · Fixed: 5.40.1-6+deb13u1
  nvd · perl · debian · 13
[perl-doc]Affected
Source package: [perl]
Details (2)
- 5.40.1-6 · all · trixie
  Affected · Fixed: 5.40.1-6+deb13u1
  nvd · perl · debian · 13
- 5.40.1-6 · all · trixie
  Affected · Fixed: 5.40.1-6+deb13u1
  nvd · perl · debian · 13
[perl-modules-5.40]Affected
Source package: [perl]
Details (2)
- 5.40.1-6 · all · trixie
  Affected · Fixed: 5.40.1-6+deb13u1
  nvd · perl · debian · 13
- 5.40.1-6 · all · trixie
  Affected · Fixed: 5.40.1-6+deb13u1
  nvd · perl · debian · 13

Observed: Oct 23, 2026, 9:44:22 PM UTC

References

[CERT-Bund public advisories] · [Debian Security Tracker] · [FIRST EPSS] · [National Vulnerability Database (NVD)] · [OSV Package Vulnerability Database] · [Red Hat security advisories and VEX] · [SUSE security advisories and VEX] · [Ubuntu Security Notices (USN)]