Vulnerability · Published Oct 19, 2026 · Assigned by apache

CVE-2026-71253Apache Johnzon: ClassConverter loads & static-initializes an attacker-named class from untrusted JSON

Critical 9.8

In plain English

A critical-severity security flaw in Apache Johnzon from Apache Software Foundation. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 32% of all known vulnerabilities).

Severity (CVSS 3.1)9.8Critical

Exploit odds (30 days)0.4%top 67.8% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official 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.

Affected products (as reported)

Vendor	Product	Versions
Apache Software Foundation	Apache Johnzon	2.0.0 – before 2.2.01.0.0 – before 1.3.1

Weakness: CWE-470 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

In plain English

Official description

Affected products (as reported)

References