Oj (Optimized JSON) is a JSON parser and Object marshaller packaged as a Ruby gem. Prior to 3.17.2, Oj::Doc iterators (each_value, each_child, each_leaf) were vulnerable to a heap use-after-free. When a Ruby block yielded during iteration calls doc.close or d.close, the document's heap memory is freed while the C iterator is still running. When control returns from the block, the iterator reads from the freed region, producing a use-after-free accessible from pure Ruby. This issue has been fixed in version 3.17.2.
| Vendor | Product | Versions |
|---|---|---|
| rubygems | oj | < 3.17.2 |
Updated severity to CRITICAL, noted no exploit exists, and added CVE-2026-54897 as a new tag.
Initial creation
