Improper input validation in Ultrajson
CVE-2026-54911
UltraJSON is a fast JSON encoder and decoder written in pure C with bindings for Python 3.7+. Prior to 5.13.0, ujson.dumps() (or ujson.dump() or ujson.encode()) have a reject_bytes=False option. When set, they may accept malformed or trunc…
Vulnerability class: Drupalgeddon 2 (CVE-2018-7600)
CVSS v3 metric
CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N.
Affected products
- Ultrajson — versions < 5.13.0
Weakness classification (CWE)
References
- security-advisories@github.com (x_refsource_CONFIRM)
- security-advisories@github.com (x_refsource_MISC)
- security-advisories@github.com (x_refsource_MISC)
Frequently asked questions
- What is CVE-2026-54911?
- CVE-2026-54911 is a medium-severity vulnerability in Ultrajson, classified under Improper Input Validation. CVSS score: 6.5/10. Published 2026-06-22.
- How severe is CVE-2026-54911?
- Medium severity. CVSS v3 base score is 6.5 out of 10.