CVE-2026-8376
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.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.44%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
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.
- CVSS 3.1
- 9.8 CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- EPSS
- 0.44% probability · 37th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-680
- Affected
- perl/perl
- Source
- 9b29abf9-4ab0-4765-b253-1875cd9b441e
References
- https://github.com/Perl/perl5/commit/5e7f119eb2bb1181be908701f22bf7068e722f1c.patchPatch
- http://www.openwall.com/lists/oss-security/2026/05/26/1Mailing List, Third Party Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.