CVE-2026-8376: perl Integer Overflow to Buffer Overflow

Vulnerability summary

CVE-2026-8376 is a critical (CVSS 9.8) Integer Overflow to Buffer Overflow vulnerability in perl. EPSS estimates a 0.48% chance of exploitation in the next 30 days, higher than 40.4% of scored vulnerabilities.

Timeline

1. 25-05-2026
   PublishedVulnerability first disclosed.
2. 08-09-2026
   Last modifiedVulnerability information updated.

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.

• CWE-680Integer Overflow to Buffer OverflowThe product performs a calculation to determine how much memory to allocate, but an integer overflow can occur that causes less memory to be allocated than expected, leading to a buffer overflow.