Bug 2499729 (CVE-2026-57432)

Summary: CVE-2026-57432 perl: Perl: Information disclosure via integer overflow in pack/unpack operations
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, 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 `S_measure_struct` function, specifically when handling `pack` and `unpack` templates with large repeat counts, can lead to an out-of-bounds heap read. This allows an attacker, by providing a specially crafted template, to read sensitive information from memory beyond the intended buffer. This could result in the disclosure of confidential data.
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Bug Depends On: 2506204    
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Description OSIDB Bzimport 2026-07-13 17:01:44 UTC 
Perl versions through 5.43.10 have an integer overflow in S_measure_struct leading to an out-of-bounds heap read in pack and unpack.

S_measure_struct adds each item's size times its repeat count to a running total with no overflow check, so a large repeat count in a pack or unpack template wraps the signed SSize_t total negative. The @, X, and x position codes then guard their moves with a signed length comparison that passes when the length is negative, advancing the buffer pointer out of bounds.

A template derived from untrusted input can read heap memory past the buffer and return it to the caller.