Bug 2495919 (CVE-2026-54901)

Summary: CVE-2026-54901 Oj: Use-After-Free in Oj::Parser array_class/hash_class GC Marking
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
Status: NEW --- QA Contact:
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Priority: medium    
Version: unspecifiedCC: eshamard, jvasik, kaycoth, rblanco
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Hardware: All   
OS: Linux   
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Description OSIDB Bzimport 2026-07-01 13:02:58 UTC 
Oj (Optimized JSON) is a JSON parser and Object marshaller packaged as a Ruby gem. In versions prior to 3.17.2, Oj::Parser in usual mode does not mark array_class and hash_class references during garbage collection, leading to Use-After-Free. If GC runs after the class is assigned but before a parse, the class object is reclaimed, leaving the parser holding a dangling VALUE. The subsequent parse call dereferences the freed object, producing a segfault. This issue has been fixed in version 3.17.2.