Affected: RubyGems: json

### Impact

A format string injection vulnerability than that lead to denial of service attacks or information disclosure, when the `allow_duplicate_key: false` parsing option is used to parse user supplied documents.

This option isn't the default, if you didn't opt-in to use it, you are not impacted.

### Patches

Patched in `2.19.2`.

### Workarounds

The issue can be avoided by not using the `allow_duplicate_key: false` parsing option.