# CVE-2026-71847: ruby-json: Ruby JSON is a JSON implementation for Ruby

CVE-2026-71847 is fixed in 2 products on 1 platform, first by DEBIAN-CVE-2026-71847, released August 13, 2026. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2026-71847
- Priority: Routine
- CVSS: n/a
- EPSS: 0.0043
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Aug 7, 2026

## 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.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | hawk2 opensuse-leap 16.0 | 2.7.2+git.1788518533.7d4dadd6-160000.1.1 | [OPENSUSE-SU-2026:22068-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-22068-1.md) | Nov 7, 2026 |
| Linux | hawk2 sles 16.0 | 2.7.2+git.1788518533.7d4dadd6-160000.1.1 | [SUSE-SU-2026:24195-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-24195-1.md) | Nov 7, 2026 |
| Linux | ruby-json Debian 14 | 2.21.2+dfsg-1 | [DEBIAN-CVE-2026-71847](https://patchblox.com/security/data/fix/linux/debian-cve-2026-71847.md) | Aug 13, 2026 |

---

Data as of 2026-11-08T06:59:42Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

Free to use with attribution: show "Data: Patchblox Patch Radar" with a link to https://patchblox.com/security/patch-radar. Terms, including what needs a written agreement: https://patchblox.com/security/patch-radar/use-the-data

Product names, logos and trademarks shown on Patch Radar belong to their respective owners. They are used only to identify the software each security fix applies to and to help readers find their platform. Their use does not imply any affiliation with, or endorsement by, those owners, and Patchblox is not affiliated with any of them.