CVE-2026-54901: Oj: Use-After-Free in Oj::Parser array_class/hash_class GC Marking

June 19, 2026

Oj::Parser in usual mode does not mark array_class and hash_class references during garbage collection. 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.

References

github.com/advisories/GHSA-vwm4-62gf-x745
github.com/ohler55/oj/security/advisories/GHSA-vwm4-62gf-x745
nvd.nist.gov/vuln/detail/CVE-2026-54901

Code Behaviors & Features

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