CVE-2026-44660
UltraJSON: Memory Leak in ujson.dump() on Write Failure
- State
- Published
- Severity
- 8.7 High
- Published
- May 27, 2026
- Updated
- May 30, 2026
- Reserved
- May 7, 2026
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.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 4.0 | 8.7 High | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N | GitHub_M |
Weaknesses
- CWE-401 Missing Release of Memory after Effective Lifetime
Affected Products
| Product | Versions |
|---|---|
ultrajsonultrajson |
|
References
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