# CVE-2022-31117: python3-ujson: UltraJSON is a fast JSON encoder and decoder written in pure C with bindings for Python 3.7+

CVE-2022-31117 is fixed in 3 products on 1 platform, first by python-ujson 1.35-2ubuntu0.1~esm1, released July 5, 2022. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2022-31117
- Priority: Routine
- CVSS: 5.9 (Medium)
- EPSS: 0.0188
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Jul 5, 2022

## Description

UltraJSON is a fast JSON encoder and decoder written in pure C with bindings for Python 3.7+. In versions prior to 5.4.0 an error occurring while reallocating a buffer for string decoding can cause the buffer to get freed twice. Due to how UltraJSON uses the internal decoder, this double free is impossible to trigger from Python. This issue has been resolved in version 5.4.0 and all users should upgrade to UltraJSON 5.4.0. There are no known workarounds for this issue.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | python-ujson Ubuntu 18.04.6 LTS (bionic) | 1.35-2ubuntu0.1~esm1 | [python-ujson 1.35-2ubuntu0.1~esm1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-python-ujson-1.35-2ubuntu0.1-esm1.md) | Jul 5, 2022 |
| Linux | python3-ujson Ubuntu 18.04.6 LTS (bionic) | 1.35-2ubuntu0.1~esm1 | [python3-ujson 1.35-2ubuntu0.1~esm1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-python3-ujson-1.35-2ubuntu0.1-esm1.md) | Jul 5, 2022 |
| Linux | python3-ujson Ubuntu 22.04.1 LTS (jammy) | 5.1.0-1ubuntu0.1~esm1 | [python3-ujson 5.1.0-1ubuntu0.1~esm1](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-python3-ujson-5.1.0-1ubuntu0.1-esm1.md) | Jul 5, 2022 |
| Linux | ujson Debian 12.15 (bookworm) | 5.4.0-1 | [DEBIAN-CVE-2022-31117](https://patchblox.com/security/data/fix/linux/debian-cve-2022-31117.md) | Jul 5, 2022 |
| Linux | ujson Debian 13.5 (trixie) | 5.4.0-1 | [DEBIAN-CVE-2022-31117](https://patchblox.com/security/data/fix/linux/debian-cve-2022-31117.md) | Jul 5, 2022 |
| Linux | ujson Debian 14 | 5.4.0-1 | [DEBIAN-CVE-2022-31117](https://patchblox.com/security/data/fix/linux/debian-cve-2022-31117.md) | Jul 5, 2022 |

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Data as of 2026-11-09T01:18:40Z 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 Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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