SB2026102310 - Unsafe reflection in Apache Johnzon

Description

This security bulletin contains information about 1 vulnerability.

1) Unsafe reflection (CVE-ID: CVE-2026-71253)

CWE-ID: CWE-470 - Use of Externally-Controlled Input to Select Classes or Code ('Unsafe Reflection')

CVSSv4: 6.3 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N]

The vulnerability allows a remote attacker to trigger execution of static initializer code in an attacker-selected class.

The vulnerability exists due to unsafe reflection in Apache Johnzon's ClassConverter when deserializing untrusted JSON. A remote attacker can supply JSON containing a chosen class name to cause that class to be loaded and its static initializer to execute.

Exploitation requires a class with a harmful static initializer already on the application's classpath and a REST POJO with a Class attribute.

Remediation

Install update from vendor's website.

References

• https://lists.apache.org/api/email.lua?id=3vgm1yo2sn9yhkvvs9lc4ro01vl3zt68
• https://github.com/apache/johnzon/commit/dd3d00634c746a2173a2518e882e85e8a151bf30