GHSA-3m6g-2423-7cp3

Ruby JSON has a format string injection vulnerability

Source: GitHub Advisory Database (reviewed) High CVE-2026-33210

Packages

Ecosystem	Package	Affected	Fixed in
RubyGems	json	>= 2.18.0, < 2.19.2	2.19.2
RubyGems	json	>= 2.16.0, < 2.17.1.2	2.17.1.2
RubyGems	json	>= 2.14.0, < 2.15.2.1	2.15.2.1

Details

As written in the advisory (Markdown source, shown as plain text).

### 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.

References

External links from the advisory. They lead to third-party sites.

https://github.com/ruby/json/security/advisories/GHSA-3m6g-2423-7cp3 web
https://nvd.nist.gov/vuln/detail/CVE-2026-33210 advisory
https://github.com/ruby/json package
https://github.com/rubysec/ruby-advisory-db/blob/master/gems/json/CVE-2026-33210.yml web