Bug 2495759 (CVE-2026-54900)

Summary: CVE-2026-54900 oj: Oj: Heap corruption via crafted JSON object key
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
Status: NEW --- QA Contact:
Severity: high Docs Contact:
Priority: high    
Version: unspecifiedCC: eshamard, jvasik, kaycoth, rblanco
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in Oj, a Ruby gem for JSON parsing. When processing a specially crafted JSON object key of a specific length (65,535 bytes) in usual mode with create_id enabled, an integer truncation vulnerability occurs. This leads to a negative size being passed to the `memcpy` function, causing heap memory corruption and crashing the process. A remote attacker could exploit this to cause a denial of service.
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Description OSIDB Bzimport 2026-07-01 00:16:25 UTC 
Oj (Optimized JSON) is a JSON parser and Object marshaller packaged as a Ruby gem. In versions prior to 3.17.2, when in usual mode with create_id enabled, Oj::Parser#parse is vulnerable to heap corruption via a negative-size memcpy. When a JSON object key is exactly 65,535 bytes long, an integer truncation in form_attr (usual.c:63) converts the length to -1 before passing it to memcpy. This causes memcpy to copy SIZE_MAX bytes (interpreted as a huge size_t), corrupting heap memory and crashing the process. The issue has been fixed in version 3.17.2.