Severity: severity: LOW. Although a class initialiser can be triggered remotely
it needs 2 separate preconditions: a) there must be a poisonous
class-initialiser on the classpath (unlikely). b) there must be a REST POJO
with a Class attribute on the project (unlikely as well)
Affected versions:
- Apache Johnzon (org.apache.johnzon:johnzon-mapper) 2.0.0 before 2.2.0
- Apache Johnzon (org.apache.johnzon:johnzon-mapper) 1.0.0 before 1.3.1
Description:
Use of Externally-Controlled Input to Select Classes or Code ('Unsafe
Reflection') vulnerability in Apache Johnzon.
ClassConverter loads & static-initializes an attacker-named class from
untrusted JSON.
This issue affects Apache Johnzon: from 1.0.0 before 2.2.0.
Users are recommended to upgrade to version 1.3.1 (javax namespace) or 2.2.0
(jakarta specification namespace), which fixes the issue.
Credit:
n0mi1k Security (finder)
References:
https://github.com/apache/johnzon/commit/dd3d00634c746a2173a2518e882e85e8a151bf30
https://github.com/apache/johnzon/commit/91e7b0d21d08d138944e2570691939739422a3d6
https://johnzon.apache.org/
https://www.cve.org/CVERecord?id=CVE-2026-71253
