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Fencer Vulns
high 7.3

CVE-2026-8376 json

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 a heap buffer overflow when compiling regular expressions with a repeated fixed string on 32-bit builds

published 2026-05-25 5 mo ago modified 2026-09-08 2 mo ago also EUVD-2026-31772

cvss
7.3
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.6%
EPSS 0.6% chance of exploitation in 30 days, percentile 47%
public exploits
0
none known

Summary

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 a heap buffer overflow when compiling regular expressions with a repeated fixed string on 32-bit builds.

Perl_study_chunk in regcomp_study.c checked the size of the joined substring buffer in characters rather than bytes. For a quantified fixed substring with a large minimum count, the byte length mincount * l could overflow SSize_t, producing an undersized SvGROW allocation; the subsequent copy writes past the end of the buffer.

A caller that compiles an attacker-controlled regular expression on a 32-bit perl build triggers a heap buffer overflow at compile time.

Patch / fix

  • perl Debian 12 5.36.0-7+deb12u4
  • perl Debian 13 5.40.1-6+deb13u1
  • perl Debian 14 5.40.1-8

debian advisories DEBIAN-CVE-2026-8376

  • perl Ubuntu 22.04 LTS 5.34.0-3ubuntu1.7
  • perl Ubuntu 24.04 LTS 5.38.2-3.2ubuntu0.3
  • perl Ubuntu 25.10 5.40.1-6ubuntu0.1
  • perl Ubuntu 26.04 LTS 5.40.1-7ubuntu0.1
  • perl Ubuntu Pro 14.04 LTS 5.18.2-2ubuntu1.7+esm7
  • perl Ubuntu Pro 18.04 LTS 5.26.1-6ubuntu0.7+esm2
  • perl Ubuntu Pro 20.04 LTS 5.30.0-9ubuntu0.5+esm2

ubuntu advisories UBUNTU-CVE-2026-8376

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • perl SLES for SAP 15 SP6, SLES for SAP 15 SP5, SLES for SAP 15 SP4 +13 more 5.26.1-150300.17.23.1
  • perl Linux Micro 6.1 5.38.2-slfo.1.1_3.1
  • perl Linux Micro 6.0 5.38.2-5.1
  • perl SLES 16.0, Linux Micro 6.2, SLES for SAP applications 16.0 5.42.0-160000.3.1
  • perl SLES LTSS Extended Security 12 SP5, SLES 12 SP5-LTSS 5.18.2-12.35.1

suse advisories SUSE-SU-2026:3558-1SUSE-SU-2026:3540-1SUSE-SU-2026:23075-1SUSE-SU-2026:23008-1SUSE-SU-2026:22847-1SUSE-SU-2026:22929-1

  • perl openSUSE Leap 16.0 5.42.0-160000.3.1

opensuse advisories openSUSE-SU-2026:21411-1

  • perl Alpine 3.24 5.42.3-r0

alpine advisories ALPINE-CVE-2026-8376

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • perl Azure Linux 3.0 5.38.2-512

azure linux advisories AZL-87357

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-8376 updated cvss 5.7

perl: Perl: Heap buffer overflow when compiling regular expressions on 32-bit builds

  • Red Hat Enterprise Linux 6 perl, perl-CGI, perl-core, perl-CPAN, perl-libs, perl-parent, +39 more Red Hat Enterprise Linux 7 perl, perl-core, perl-CPAN, perl-libs, perl-tests, perl-macros, +11 more
    affected: workaround, no fix planned “Out of support scope”
  • Red Hat Enterprise Linux 8 perl, perl-IO, perl-libs, perl-open, perl-Test, perl-Errno, +19 more Red Hat Enterprise Linux 9 perl, perl-B, perl-if, perl-IO, perl-ph, perl-lib, +92 more
    not affected: inline mitigations already exist
  • Red Hat Enterprise Linux 10 perl Red Hat Hardened Images perl
    not affected: component not present
  • Red Hat OpenShift Container Platform 4 openshift/ose-rhel-coreos-8, openshift/ose-rhel-coreos-9
    not affected: vulnerable code not in execute path

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
5 mo ago

Exploit prediction

0.57% chance of exploitation in the next 30 days, higher than 47% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CISA ADP 3.1 7.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
NVD 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CNA 3.1 7.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L

Classification

Weakness
  • CWE-680 Integer Overflow to Buffer Overflow

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.