CPANSA-perl-2026-15534: perl vulnerability

Publisher giterlizzi Document category csaf_security_advisory
Initial release date 2026-08-09T00:00:00 Engine CSAF Perl Toolkit 0.26
Current release date 2026-08-09T00:00:00 Build Date
Current version 1 Status final
CVSS v3.1 Base Score 5.7 Severity Medium
Original language Language en
Also referred to

Vulnerability Description

Perl versions through 5.45.1 have out-of-bounds heap reads and writes during regular expression matching via an undersized superlinear cache in S_regmatch.

The regex engine's superlinear cache holds one bit per subject position for each participating WHILEM node, so the bit count is the subject length plus one times the number of nodes. Nothing checks that product for positive overflow of the signed 32-bit count: a 286331153 byte subject matched against a pattern with 15 participating nodes stores the count as 14, leaving a two byte cache. The cache is then indexed from the real match position and node number, so reads go past the end of the allocation, and on failure CACHEsayNO sets a bit past it.

A caller that matches an attacker controlled subject of this size against a pattern of this shape can crash the process or corrupt heap memory.

Vulnerabilities

CVE-2026-15534

Vulnerability Description

Perl versions through 5.45.1 have out-of-bounds heap reads and writes during regular expression matching via an undersized superlinear cache in S_regmatch.

The regex engine's superlinear cache holds one bit per subject position for each participating WHILEM node, so the bit count is the subject length plus one times the number of nodes. Nothing checks that product for positive overflow of the signed 32-bit count: a 286331153 byte subject matched against a pattern with 15 participating nodes stores the count as 14, leaving a two byte cache. The cache is then indexed from the real match position and node number, so reads go past the end of the allocation, and on failure CACHEsayNO sets a bit past it.

A caller that matches an attacker controlled subject of this size against a pattern of this shape can crash the process or corrupt heap memory.

Weakness CWE-125 : Out-of-bounds Read

Product status

Known affected
Product Score
perl greater than 0
CVSS Version CVSS Vector CVSS Base Score CVSS Base Severity
3.1 CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:H 5.7 Medium

giterlizzi

Namespace: https://github.com/giterlizzi/

gdt@cpan.org

References

Revision history

Version Date of the revision Summary of the revision
1 Sun Aug 9 00:00:00 2026 First release

Sharing rules

TLP:WHITE
For the TLP version see: https://www.first.org/tlp/