Oj (Optimized JSON) is a JSON parser and Object marshaller packaged as a Ruby gem. In versions prior to 3.17.2, when in object mode, Oj.dump is vulnerable to a heap buffer overflow when serializing Exception objects with a large :indent value. The serializer allocates a buffer sized for the object's attributes but does not account for the indent bytes added on each write. With indent: 5000, the accumulation of 5,000-byte indent strings overflows the 13,150-byte heap allocation, corrupting adjacent heap memory. This issue has been fixed in version 3.17.2.

A flaw was found in Oj (Optimized JSON), a Ruby gem used for processing JSON data. This vulnerability occurs when the software attempts to serialize (convert into a format for storage or transmission) Exception objects with a very large indentation setting. The internal process for handling this serialization does not properly manage memory, leading to a heap buffer overflow. This memory corruption could allow an attacker to disrupt the application, causing a denial of service, or potentially execute unauthorized code.

Red Hat's only product shipping the Oj Ruby gem (Compliance Backend) already includes version 3.17.3, which contains the fix for this vulnerability. No Red Hat products are affected. https://www.cve.org/CVERecord?id=CVE-2026-54896 https://nvd.nist.gov/vuln/detail/CVE-2026-54896 https://github.com/ohler55/oj/security/advisories/GHSA-35w3-pjm6-wj95