Description

UltraJSON is a fast JSON encoder and decoder written in pure C with bindings for Python 3.7+. Versions 5.4.0 through 5.11.0 contain an accumulating memory leak in JSON parsing large (outside of the range [-2^63, 2^64 - 1]) integers. The leaked memory is a copy of the string form of the integer plus an additional NULL byte. The leak occurs irrespective of whether the integer parses successfully or is rejected due to having more than sys.get_int_max_str_digits() digits, meaning that any sized leak per malicious JSON can be achieved provided that there is no limit on the overall size of the payload. Any service that calls ujson.load()/ujson.loads()/ujson.decode() on untrusted inputs is affected and vulnerable to denial of service attacks. This issue has been fixed in version 5.12.0.

INFO

Published Date :

2026-03-20T01:31:30.207Z

Last Modified :

2026-03-20T16:38:13.493Z

Source :

GitHub_M
AFFECTED PRODUCTS

The following products are affected by CVE-2026-32874 vulnerability.

Vendors Products
Ultrajson
  • Ultrajson
Ultrajson Project
  • Ultrajson

CVSS Vulnerability Scoring System

Detailed values of each vector for above chart.
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Availability Impact