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CVE-2026-54901

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

CVSS 6.3 MEDIUMEPSS 0.3%CWE-416
Vexday Risk Score
13Low
SSVC decision (CISA)
Track
No exploitation signal → monitor
CVSS 6.3EPSS 0.3%KEV nãoPoC Nuclei Metasploit Patch
Lifecycle
30 Jun 2026Published on NVD
Recommendation: Monitor — no exploitation signal at the moment.
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.
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
Affected products
ohler55 · oj

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