CVE-2026-33012 is a high-severity (CVSS 7.5) CWE-770 vulnerability in io.micronaut:micronaut-http-server. O3 Security confirms whether CVE-2026-33012 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Micronaut Framework vulnerable to a Denial of Service in HTML error response caching
Real-World Exposure
io.micronaut:micronaut-http-serverReal-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 4.7.0 through 4.10.16 used an unbounded ConcurrentHashMap cache with no eviction policy in its DefaultHtmlErrorResponseBodyProvider. If the application throws an exception whose message may be influenced by an attacker, (for example, including request query value parameters) it could be used by remote attackers to cause an unbounded heap growth and OutOfMemoryError, leading to DoS. This issue has been fixed in version 4.10.7.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| ☕Maven | io.micronaut:micronaut-http-server | ≥ 4.7.0&&< 4.10.17 | 4.10.17 |
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-http-server. 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-http-server to 4.10.17 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-33012 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-2026-33012 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-2026-33012. 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-2026-33012 in your dependencies?
O3 detects CVE-2026-33012 across Maven dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.