CVE-2026-44660
Fixed in a distro release EPSS <1%CVSS 8.7
UltraJSON is a fast JSON encoder and decoder written in pure C with bindings for Python 3.7+. Prior to 5.12.1, when ujson.dump() writes to a file-like object and the write operation raises an exception, the serialized JSON string object is not decremented, leaking memory. Each failed write operation leaks the full size of the serialized payload. This vulnerability is fixed in 5.12.1.
Products: ultrajson
Fixed upstream
| Ecosystem | Package | Fixed in |
|---|---|---|
| PyPI | ujson | 5.12.1 |
Distro releases
| Release | Package | Fixed in |
|---|---|---|
| Chainguard | label-studio | 1.23.0-r5 |
| Debian 12 | ujson | no fix |
| Debian 13 | ujson | no fix |
| Debian 14 | ujson | 5.13.0-1 |
| SUSE Linux Enterprise High Performance Computing 15 SP4-ESPOS | python-ujson | 1.35-150100.3.13.1 |
| SUSE Linux Enterprise High Performance Computing 15 SP4-LTSS | python-ujson | 1.35-150100.3.13.1 |
| SUSE Linux Enterprise High Performance Computing 15 SP5-ESPOS | python-ujson | 1.35-150100.3.13.1 |
| SUSE Linux Enterprise High Performance Computing 15 SP5-LTSS | python-ujson | 1.35-150100.3.13.1 |
| SUSE Linux Enterprise Module for Development Tools 15 SP7 | python-ujson | 1.35-150100.3.13.1 |
| SUSE Linux Enterprise Module for Package Hub 15 SP7 | python-ujson | 1.35-150100.3.13.1 |
| SUSE Linux Enterprise Server 15 SP4-LTSS | python-ujson | 1.35-150100.3.13.1 |
| SUSE Linux Enterprise Server 15 SP5-LTSS | python-ujson | 1.35-150100.3.13.1 |
| SUSE Linux Enterprise Server 15 SP6-LTSS | python-ujson | 1.35-150100.3.13.1 |
| SUSE Linux Enterprise Server 16.0 | python-ujson | 5.10.0-160000.3.1 |
| SUSE Linux Enterprise Server for SAP Applications 15 SP4 | python-ujson | 1.35-150100.3.13.1 |
| SUSE Linux Enterprise Server for SAP Applications 15 SP5 | python-ujson | 1.35-150100.3.13.1 |
| SUSE Linux Enterprise Server for SAP Applications 15 SP6 | python-ujson | 1.35-150100.3.13.1 |
| SUSE Linux Enterprise Server for SAP applications 16.0 | python-ujson | 5.10.0-160000.3.1 |
| Ubuntu 14.04 LTS | pandas | no fix |
| Ubuntu 16.04 LTS | collada2gltf | no fix |
| Ubuntu 16.04 LTS | pandas | no fix |
| Ubuntu 18.04 LTS | collada2gltf | no fix |
| Ubuntu 18.04 LTS | pandas | no fix |
| Ubuntu 20.04 LTS | pandas | no fix |
| Ubuntu 22.04 LTS | collada2gltf | no fix |
| Ubuntu 22.04 LTS | pandas | no fix |
| Ubuntu 24.04 LTS | pandas | no fix |
| Ubuntu 25.10 | pandas | no fix |
| Ubuntu 25.10 | ujson | no fix |
| Ubuntu 26.04 LTS | pandas | no fix |
| Ubuntu 26.04 LTS | ujson | no fix |
| Ubuntu 26.10 | pandas | no fix |
| Ubuntu 26.10 | ujson | no fix |
| Ubuntu Pro 16.04 LTS | ujson | no fix |
| Ubuntu Pro 18.04 LTS | ujson | no fix |
| Ubuntu Pro 20.04 LTS | ujson | no fix |
| Ubuntu Pro 22.04 LTS | ujson | no fix |
| Ubuntu Pro 24.04 LTS | ujson | no fix |
| openSUSE Leap 16.0 | python-ujson | 5.10.0-160000.3.1 |