Memory leak in ultrajson - CVE-2026-44660
Published: May 11, 2026
Vulnerability identifier: #VU130990
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-2026-44660
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 objToJSONFile() function when handling write failures in ujson.dump() to a file-like object. A remote attacker can trigger repeated failed write operations to cause a denial of service.
Each failed write leaks the full size of the serialized JSON payload.
Remediation
Install security update from vendor's website.