CVE-2026-33012: Micronaut Framework vulnerable to a Denial of Service in HTML error response caching
DefaultHtmlErrorResponseBodyProvider in io.micronaut:micronaut-http-server since 4.7.0 and until 4.10.7 used an unbounded ConcurrentHashMap cache with no eviction policy. If the application throws an exception whose message may be influenced by an attacker, for example, including request query value parameters, this could be used by remote attackers to cause a denial of service (unbounded heap growth and OutOfMemoryError).
Fixed via: https://github.com/micronaut-projects/micronaut-core/commit/1e2ba2c14386af3d47751732d02053a72b0b49b3
Other sources
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.
— MITRE
Affected Software
Remediation
Event History
Frequently Asked Questions
What is the severity of CVE-2026-33012?
CVE-2026-33012 has a severity rating that indicates a potential risk of denial of service due to the unbounded cache leading to resource exhaustion.
How do I fix CVE-2026-33012?
To fix CVE-2026-33012, upgrade the `io.micronaut:micronaut-http-server` package to version 4.10.17 or later.
What causes CVE-2026-33012?
CVE-2026-33012 is caused by an unbounded `ConcurrentHashMap` cache in `DefaultHtmlErrorResponseBodyProvider` that lacks an eviction policy.
What software versions are affected by CVE-2026-33012?
CVE-2026-33012 affects `io.micronaut:micronaut-http-server` versions from 4.7.0 to 4.10.7.
Is CVE-2026-33012 exploitable remotely?
Yes, CVE-2026-33012 can be exploited by an attacker who can influence exception messages, potentially leading to Denial of Service.