CVE-2026-33012 is a high-severity (CVSS 7.5) CWE-770 vulnerability in io.micronaut:micronaut-http-server. A fix is available for io.micronaut:micronaut-http-server — see the affected versions and patch details below.
Micronaut Framework vulnerable to a Denial of Service in HTML error response caching
Exploitation Status
No confirmed exploitation observed yet
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-33012.
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.
How urgent is this, really
CVE-2026-33012 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 378,156 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
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 | 4.10.17io.micronaut:micronaut-http-server: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, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
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 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2026-33012 can be triaged on real exposure rather than presence alone.
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 Security finds CVE-2026-33012 across Maven dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.