CVE-2026-33013
CVE-2026-33013 is a CWE-835 vulnerability in io.micronaut:micronaut-json-core. O3 Security confirms whether CVE-2026-33013 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Micronaut vulnerable to DoS via crafted form-urlencoded body binding with descending array indices
Blast Radius
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
Micronaut Framework is a JVM-based full stack Java framework designed for building modular, easily testable JVM applications. Versions prior to both 4.10.16 and 3.10.5 do not correctly handle descending array index order during form-urlencoded body binding in theJsonBeanPropertyBinder::expandArrayToThreshold, which allows remote attackers to cause a DoS (non-terminating loop, CPU exhaustion, and OutOfMemoryError) via crafted indexed form parameters (e.g., authors[1].name followed by authors[0].name). This issue has been fixed in versions 4.10.16 and 3.10.5.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| ☕Maven | io.micronaut:micronaut-json-core | ≥ 4.0.0-M1&&< 4.10.16 | 4.10.16 |
| ☕Maven | io.micronaut:micronaut-json-core | ≥ 3.9.0&&< 3.10.5 | 3.10.5 |
| ☕Maven | io.micronaut:micronaut-json-core | all versions | 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. 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 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 CVE-2026-33013 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 CVE-2026-33013 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 CVE-2026-33013. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-33013 in your dependencies?
O3 detects CVE-2026-33013 across Maven dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.