Perl versions through 5.43.10 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.

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Fixes

Solution

Upgrade to a future perl release, or apply the upstream patch.


Workaround

On 32-bit perl builds, avoid compiling regular expressions from untrusted input until a fixed release is installed.

History

Wed, 27 May 2026 19:30:00 +0000

Type Values Removed Values Added
Metrics cvssV3_1

{'score': 9.8, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'}

ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

cvssV3_1

{'score': 7.3, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L'}


Wed, 27 May 2026 18:45:00 +0000

Type Values Removed Values Added
First Time appeared Perl
Perl perl
CPEs cpe:2.3:a:perl:perl:*:*:*:*:*:*:*:*
Vendors & Products Perl
Perl perl
Metrics cvssV3_1

{'score': 9.8, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'}


Tue, 26 May 2026 13:45:00 +0000

Type Values Removed Values Added
References

Tue, 26 May 2026 03:15:00 +0000

Type Values Removed Values Added
First Time appeared Shay
Shay perl
Vendors & Products Shay
Shay perl

Tue, 26 May 2026 00:15:00 +0000

Type Values Removed Values Added
Description Perl versions through 5.43.10 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.
Title Perl versions through 5.43.10 have a heap buffer overflow when compiling regular expressions with a repeated fixed string on 32-bit builds
Weaknesses CWE-680
References

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: CPANSec

Published:

Updated: 2026-05-27T18:04:00.329Z

Reserved: 2026-05-12T08:15:41.456Z

Link: CVE-2026-8376

cve-icon Vulnrichment

Updated: 2026-05-26T03:06:00.816Z

cve-icon NVD

Status : Modified

Published: 2026-05-26T00:16:57.150

Modified: 2026-05-27T19:16:24.767

Link: CVE-2026-8376

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-05-26T03:00:13Z

Weaknesses