Vulnerability · Published May 25, 2026 · Assigned by CPANSec
CVE-2026-8376Perl 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
High 7.3
In plain English
A high-severity security flaw in perl. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.6% (higher than 47% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine:v3.24 | perl | 5.42.3-r0 | ALPINE-CVE-2026-8376 |
| Debian:12 | perl | 5.36.0-7+deb12u4 | DEBIAN-CVE-2026-8376 |
| Debian:13 | perl | 5.40.1-6+deb13u1 | DEBIAN-CVE-2026-8376 |
| Debian:14 | perl | 5.40.1-8 | DEBIAN-CVE-2026-8376 |
| Ubuntu:22.04:LTS | perl | 5.34.0-3ubuntu1.7 | UBUNTU-CVE-2026-8376 |
| Ubuntu:24.04:LTS | perl | 5.38.2-3.2ubuntu0.3 | UBUNTU-CVE-2026-8376 |
| Ubuntu:25.10 | perl | 5.40.1-6ubuntu0.1 | USN-8467-2 |
| Ubuntu:25.10 | perl | 5.40.1-6ubuntu0.1 | UBUNTU-CVE-2026-8376 |
| Ubuntu:26.04:LTS | perl | 5.40.1-7ubuntu0.1 | UBUNTU-CVE-2026-8376 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| perl | 0 – before 5.40.5-RC15.41.0 – before 5.42.3-RC15.43.0 – before 5.43.11 |
Weakness: CWE-680 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L