{
  "claim": {
    "argus_claim_ref": null,
    "attacker_control": null,
    "claimed_surface": "library_api",
    "expected_impact": null,
    "finding_id": null,
    "id": null,
    "required_entrypoint_detail": null,
    "required_entrypoint_kind": "function_call",
    "submission_reason": "ticket_derived",
    "trigger_class": "library_api",
    "upstream_verdicts": null
  },
  "latest_description": "Oj (Optimized JSON) is a JSON parser and Object marshaller packaged as a Ruby gem. In versions prior to 3.17.3, Oj.load in :object mode reads uninitialized stack memory (and, for long keys, reads out of bounds) when parsing a JSON object whose key is 254 bytes or longer. In ext/oj/intern.c, form_attr() handles the long-key path by allocating a heap buffer, populating it with the attribute name, and then freeing it — but it passes the uninitialized stack buffer buf (not b) to rb_intern3(). rb_intern3 therefore reads len + 1 bytes of uninitialized stack memory. When the key length is >= 256, it also reads out of bounds past the 256-byte buf. The resulting bytes are interned and can reach the caller via the produced Symbol or via the EncodingError message raised on invalid UTF-8, leaking process stack contents. Fixed in version 3.17.3.",
  "product": "ohler55/oj",
  "severity": "medium",
  "status": "open",
  "summary": "Oj Ruby gem uninitialized stack memory leak via long JSON keys",
  "ticket_id": "CVE-2026-54500"
}