Bug 2512950 (CVE-2026-15534)

Summary: CVE-2026-15534 perl: Perl: Arbitrary code execution via out-of-bounds memory access in regular expression engine.
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: akhatavk, aos-team-art-private, asdas, crizzo, dpaolell, gtanzill, jbuscemi, jdelft, jupierce, kshier, lgarciaa, mbiarnes, ppalepu, ppostler, prdhamdh, rhel-process-autobot, sdawley, sghai, sidsharm, stcannon, suppawar, teagle, vlaad, watson-tool-maintainers, yguenane
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in Perl. An integer overflow vulnerability in the regular expression engine's superlinear cache calculation can lead to out-of-bounds memory reads and writes. A remote attacker could exploit this by providing a specially crafted, large input string during regular expression matching. This could result in a denial of service (DoS) due to a process crash or potentially lead to heap memory corruption, enabling arbitrary code execution.
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Description OSIDB Bzimport 2026-08-09 18:01:21 UTC 
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.