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

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-15534
StatePUBLISHED
AssignerCPANSec
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-08-09 18:16:42 UTC
Updated2026-09-08 22:17:38 UTC
DescriptionPerl 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.

Risk And Classification

Primary CVSS: v3.1 5.7 MEDIUM from ADP

CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:H

EPSS: 0.001610000 probability, percentile 0.056230000 (date 2026-09-08)

Problem Types: CWE-125 | CWE-190 | CWE-787 | CWE-190 CWE-190 Integer Overflow or Wraparound | CWE-125 CWE-125 Out-of-bounds Read | CWE-787 CWE-787 Out-of-bounds Write

VersionSourceTypeScoreSeverityVector
3.1ADPDECLARED5.7MEDIUMCVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:H
3.1134c704f-9b21-4f2e-91b3-4a467353bcc0Secondary5.7MEDIUMCVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:H

CVSS v3.1 Breakdown

Attack Vector
Local
Attack Complexity
High
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
Low
Availability
High

CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:H

References

ReferenceSourceLinkTags
github.com/Perl/perl5/commit/568e6fd238867bb9e99fa3f47cba3169009239e0.patch 9b29abf9-4ab0-4765-b253-1875cd9b441e github.com
www.openwall.com/lists/oss-security/2026/08/09/13 af854a3a-2127-422b-91ae-364da2661108 www.openwall.com
www.openwall.com/lists/oss-security/2026/08/09/12 af854a3a-2127-422b-91ae-364da2661108 www.openwall.com
github.com/Perl/perl5/commit/54cf3d44cbbedd17d774e9a37921963e8fd5d0cb.patch 9b29abf9-4ab0-4765-b253-1875cd9b441e github.com
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Additional Advisory Data

Solutions

CNA: Apply the upstream patches. The fix is included in the Perl 5.45.2 development release.

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