CVE-2026-44660 — UltraJSON: Memory Leak in ujson.dump() on Write Failure
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 opera…
Published: 2026-05-27 · CVSS: 8.7 · CVSS 4.0
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.
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7