GHSA-43w5-mmxv-cpvh — micronaut-json-core
Fix: micronaut-projects/micronaut-core#12410GHSA-43w5-mmxv-cpvh is a CWE-835 vulnerability in io.micronaut:micronaut-json-core. A fix is available for io.micronaut:micronaut-json-core — see the affected versions and patch details below.
Micronaut vulnerable to DoS via crafted form-urlencoded body binding with descending array indices
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
Exploitation and automatability from CISA’s SSVC triage for GHSA-43w5-mmxv-cpvh.
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.
Real-World Exposure
io.micronaut:micronaut-json-core☕io.micronaut:micronaut-json-core☕io.micronaut:micronaut-json-coreReal-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
In JsonBeanPropertyBinder::expandArrayToThreshold in io.micronaut:micronaut-json-core before Micronaut 4 4.10.16 and in Micronaut 3 before 3.10.5 does not correctly handle descending array index order during form-urlencoded body binding, which allows remote attackers to cause a denial of service (non-terminating loop, CPU exhaustion, and OutOfMemoryError) via crafted indexed form parameters (e.g., authors[1].name followed by authors[0].name).
Example
With such an application
package dosform;
import io.micronaut.http.HttpResponse;
import io.micronaut.http.MediaType;
import io.micronaut.http.annotation.Body;
import io.micronaut.http.annotation.Consumes;
import io.micronaut.http.annotation.Controller;
import io.micronaut.http.annotation.Get;
import io.micronaut.http.annotation.Post;
import io.micronaut.http.annotation.Produces;
import java.net.URI;
@Controller
class HomeController {
@Produces(MediaType.TEXT_HTML)
@Get
String index() {
return """
<!DOCTYPE html>
<html>
<head>
<title></title>
</head>
<body>
<form action="/submit" method="post">
<label for="firstAuthor">Fist Author</label>
<input id="firstAuthor" name="authors[0].name" type="text"/>
<label for="secondAuthor">Second Author</label>
<input id="secondAuthor" name="authors[1].name" type="text"/>
<label for="thirdAuthor">Third Author</label>
<input id="thirdAuthor" name="authors[2].name" type="text"/>
<button type="submit">Submit</button>
</form>
</body>
</html>
""";
}
@Consumes(MediaType.APPLICATION_FORM_URLENCODED)
@Post("/submit")
HttpResponse<?> submit(@Body Book book) {
return HttpResponse.seeOther(URI.create("/"));
}
}
package dosform;
import io.micronaut.core.annotation.Introspected;
import java.util.Objects;
@Introspected
public class Author {
private String name;
public String getName() { return name; }
public void setName(String name) { this.name = name; }
@Override
public final boolean equals(Object o) {
if (!(o instanceof Author)) return false;
Author author = (Author) o;
return Objects.equals(name, author.name);
}
@Override
public int hashCode() {
return Objects.hashCode(name);
}
@Override
public String toString() {
return "Author{" +
"name='" + name + '\'' +
'}';
}
}
package dosform;
import io.micronaut.core.annotation.Introspected;
import java.util.List;
import java.util.Objects;
@Introspected
public class Book {
private List<Author> authors;
public List<Author> getAuthors() { return authors; }
public void setAuthors(List<Author> authors) { this.authors = authors; }
@Override
public final boolean equals(Object o) {
if (!(o instanceof Book)) return false;
Book book = (Book) o;
return Objects.equals(authors, book.authors);
}
@Override
public int hashCode() {
return Objects.hashCode(authors);
}
@Override
public String toString() {
return "Book{" +
"authors=" + authors +
'}';
}
}
Sending curl -v -X POST 'http://127.0.0.1:8080/submit' -H 'Content-Type: application/x-www-form-urlencoded' --data-urlencode 'authors[1].name=RobertGalbraith' --data-urlencode 'authors[0].name=JKRowling' causes sustained CPU usage and unbounded memory growth (eventually OutOfMemoryError).
Patches
For Micronaut 4, the problem has been patched in micronaut-core, dependencies with group id io.micronaut, since 4.10.16.
For Micronaut 3, the problem has been patched since 3.10.5
Users upgrade to the latest version of the framework.
Workarounds
There is no way for users to fix or remediate the vulnerability without upgrading.
References
PR Fix: https://github.com/micronaut-projects/micronaut-core/pull/12410
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| ☕Maven | io.micronaut:micronaut-json-core | ≥ 4.0.0-M1&&< 4.10.16 | 4.10.16io.micronaut:micronaut-json-core:4.10.16 |
| ☕Maven | io.micronaut:micronaut-json-core | ≥ 3.9.0&&< 3.10.5 | 3.10.5io.micronaut:micronaut-json-core:3.10.5 |
| ☕Maven | io.micronaut:micronaut-json-core | all versions | 3.8.13io.micronaut:micronaut-json-core:3.8.13 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for io.micronaut:micronaut-json-core, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update io.micronaut:micronaut-json-core to 4.10.16 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-43w5-mmxv-cpvh 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 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-43w5-mmxv-cpvh can be triaged on real exposure rather than presence alone.
Tailored to GHSA-43w5-mmxv-cpvh. 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-43w5-mmxv-cpvh in your dependencies?
O3 Security finds GHSA-43w5-mmxv-cpvh across Maven dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.