CVE-2026-54500
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. The interned bytes can surface to the caller, disclosing process stack memory. In ext/oj/intern.c, form_attr() handles the long-key path by allocating a heap buffer, `b`, populating it with the attribute name, and then freeing it — but it passed 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. This issue has been fixed in version 3.17.3.
- CVSS 3.1
- 5.3
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N - EPSS
- 0.2% chance of exploitation in the next 30 days; higher than 9% of CVEs (scores of 2026-10-25)
- CWEs
- CWE-125, CWE-908
- Published
- Modified
- Record from
- the NVD, synced
Packages (OSV)
| Advisory | Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|---|
| GHSA-fm7p-mprw-wjm9 | RubyGems | oj | <3.17.3 | 3.17.3 |