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
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
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 |
Affected Products
micronautobjectcomputingDetection & 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
Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.Source: Red Hat security advisory for CVE-2026-33012 (CC BY 4.0)
Frequently Asked Questions
Is CVE-2026-33012 in your dependencies?
Find it across Maven, including transitive dependencies.