CVE-2026-71253
9.8CriticalPublished 19 Oct 2026 · NVD status: Deferred · AI triage by gemini-3.8-flash
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
- Impact
- Full C/I/A compromise
- Weakness
- CWE-470
Impact
Remote, unauthenticated attackers can execute arbitrary code by passing crafted JSON to applications that parse untrusted input. They only need network access to an endpoint consuming Johnzon-parsed JSON.
Root cause
ClassConverter uses unsafe reflection to load and statically initialize attacker-specified classes directly from untrusted JSON payloads.
Affected systems
Apache Johnzon 1.0.0 before 2.2.0
CVSS v3.1 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Fix & remediation
Upgrade your dependencies to Apache Johnzon 1.3.1 (if using the javax namespace) or 2.2.0 (if using the jakarta namespace). No interim mitigations or workarounds are documented.
$ mvn dependency:tree | grep -i johnzonAI-suggested. Run it in staging first and check it against the vendor advisory. Why?
NVD 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.