Memory leak in ultrajson - CVE-2026-32874
Published: April 27, 2026
Vulnerability identifier: #VU128154
CSH Severity: Medium
CVSSv4.0: 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/E:U/U:Green
CVE-ID: CVE-2026-32874
CWE-ID: CWE-401
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerable software:
ultrajson
ultrajson
Software vendor:
ultrajson
ultrajson
Description
The vulnerability allows a remote attacker to cause a denial of service.
The vulnerability exists due to missing release of memory after effective lifetime in the JSON parser when parsing large integer values in untrusted JSON input. A remote attacker can send a specially crafted JSON payload containing large integers to cause a denial of service.
The issue is triggered for integers outside the range [-2^63, 2^64 - 1], and the leak occurs even if parsing fails because the integer exceeds sys.get_int_max_str_digits().
Remediation
Install security update from vendor's website.