CVE-2026-71253 PUBLISHED

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.

• n0mi1k Security finder

• https://github.com/apache/johnzon/commit/dd3d00634c746a2173a2518e882e85e8a151bf30
• https://github.com/apache/johnzon/commit/91e7b0d21d08d138944e2570691939739422a3d6
• https://lists.apache.org/thread.html/3vgm1yo2sn9yhkvvs9lc4ro01vl3zt68

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