Vulnerability Description
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.
CVSS Score
HIGH
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Ultrajson Project | Ultrajson | < 5.12.1 |
Related Weaknesses (CWE)
References
- https://github.com/ultrajson/ultrajson/commit/82af1d0ac01d09aa40c887b460d44b9d9fPatch
- https://github.com/ultrajson/ultrajson/releases/tag/5.12.1ProductRelease Notes
- https://github.com/ultrajson/ultrajson/security/advisories/GHSA-c38f-wx89-p2xgExploitMitigationPatch
- https://github.com/ultrajson/ultrajson/security/advisories/GHSA-c38f-wx89-p2xgExploitMitigationPatch
FAQ
What is CVE-2026-44660?
CVE-2026-44660 is a vulnerability with a CVSS score of 7.5 (HIGH). 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 exceptio...
How severe is CVE-2026-44660?
CVE-2026-44660 has been rated HIGH with a CVSS base score of 7.5/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-44660?
Check the references section above for vendor advisories and patch information. Affected products include: Ultrajson Project Ultrajson.