Vulnerability Description
Ruby JSON is a JSON implementation for Ruby. From 2.20.0 until 2.21.2, Ruby's JSON native C extension clears the consumed JSON::ResumableParser input buffer but leaves state.start, state.cursor, and state.end pointing into released storage. When partial_value reconstructs an incomplete object containing duplicate keys, the duplicate-key warning path calls cursor_position, which dereferences those stale pointers. This results in a heap-use-after-free and can terminate the Ruby process. An attacker who can supply JSON stream data to an application using JSON::ResumableParser may cause process termination when the application calls partial_value on incomplete attacker-controlled input containing duplicate object keys. This issue has been fixed in version 2.21.2.
Related Weaknesses (CWE)
References
- https://github.com/ruby/json/security/advisories/GHSA-9hj4-r449-hfvc
- https://github.com/ruby/json/security/advisories/GHSA-9hj4-r449-hfvc
FAQ
What is CVE-2026-71847?
CVE-2026-71847 is a documented vulnerability. Ruby JSON is a JSON implementation for Ruby. From 2.20.0 until 2.21.2, Ruby's JSON native C extension clears the consumed JSON::ResumableParser input buffer but leaves state.start, state.cursor, and s...
How severe is CVE-2026-71847?
CVSS scoring is not yet available for CVE-2026-71847. Check NVD for updates.
Is there a patch for CVE-2026-71847?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.