CVE-2026-33012: Micronaut http server Denial of Service Vulnerability

HIGH
Advisory Identifier: GHSA-2hcp-gjrf-7fhc
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CVSS 7.5
CWE-770
Published
Advisory Summary

CVE-2026-33012 is a HIGH (CVSS 7.5) denial of service vulnerability (CWE-770: Allocation of Resources Without Limits or Throttling) affecting Micronaut http server libraries in the Maven ecosystem. The issue involves micronaut framework vulnerable to a denial of service in html error response caching. Remediation is available by upgrading affected packages to version 4.10.17.

CVE-2026-33012 at a Glance

CVE Identifier CVE-2026-33012
GHSA Identifier GHSA-2hcp-gjrf-7fhc
Severity HIGH
CVSS v3.1 Base Score 7.5
CWE Classification CWE-770: Allocation of Resources Without Limits or Throttling
Affected Product Micronaut http server
Package Ecosystem Maven
Published Date
Last Updated

Security Impact

CVSS: 7.5

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required None (PR:N)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality None (C:N)
Integrity None (I:N)
Availability High (A:H)

How to Fix CVE-2026-33012

To remediate this vulnerability, upgrade all affected Micronaut http server dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

io.micronaut:micronaut-http-server fixed: 4.10.17 
<dependency>
    <groupId>io.micronaut</groupId>
    <artifactId>micronaut-http-server</artifactId>
    <version>4.10.17</version>
</dependency>
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

mvn dependency:tree -Dincludes=io.micronaut

How to Check if You Are Affected

To determine whether your Java application is affected by CVE-2026-33012, inspect your build dependencies using the Maven Dependency Plugin:

mvn dependency:tree -Dincludes=io.micronaut

Analyze the terminal output to locate any version of Micronaut http server in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 4.10.17), your application is affected.

Note: The mvn dependency:tree -Dincludes=io.micronaut command inspects the resolved dependency graph declared in your project's POM files; it does not perform automated security scanning or inspect runtime dynamic classpaths. Always verify runtime container classpaths and shaded JARs.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-770: Allocation of Resources Without Limits or Throttling, where the product allocates a reusable resource or group of resources on behalf of an actor without imposing any intended restrictions on the size or number of resources that can be allocated. In Micronaut http server, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

`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

CVE-2026-33012 Affected Micronaut http server Versions

1 component(s)
Fixed Versions:
4.10.17
Product / Package Ecosystem Affected Versions Fixed Version
io.micronaut:micronaut-http-server
maven/io.micronaut/micronaut-http-server
Maven
≥ 4.7.0
< 4.10.17
4.10.17

References

GitHub Advisory / Wiki ADVISORY
https://github.com/micronaut-projects/micronaut-core/security/advisories/GHSA-2hcp-gjrf-7fhc
NVD — CVE-2026-33012 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-33012
Security Fix Commit FIX COMMIT
https://github.com/micronaut-projects/micronaut-core/commit/1e2ba2c14386af3d47751732d02053a72b0b49b3
Micronaut http server Source Repository REPOSITORY
https://github.com/micronaut-projects/micronaut-core
Micronaut http server Release RELEASE
https://github.com/micronaut-projects/micronaut-core/releases/tag/v4.10.17

Frequently Asked Questions

What is CVE-2026-33012?
CVE-2026-33012 is a security vulnerability in Micronaut http server involving Micronaut Framework vulnerable to a Denial of Service in HTML error response caching under CWE-770: Allocation of Resources Without Limits or Throttling.
Which Micronaut http server versions are affected?
Affected versions include releases prior to 4.10.17 across affected packages: io.micronaut:micronaut-http-server.
What version fixes CVE-2026-33012?
Upgrading to 4.10.17 (or the latest patched release for your respective branch) resolves the vulnerability.
Is micronaut-http-server affected?
Yes, io.micronaut:micronaut-http-server is affected in releases prior to 4.10.17. Upgrade your dependency to 4.10.17 or later.
What is the CVSS score of CVE-2026-33012?
CVE-2026-33012 has a CVSS v3.1 base score of 7.5 (HIGH) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.
What CWE is associated with CVE-2026-33012?
CVE-2026-33012 is classified under CWE-770: Allocation of Resources Without Limits or Throttling (The product allocates a reusable resource or group of resources on behalf of an actor without imposing any intended restrictions on the size or number of resources that can be allocated.).
How can I check Maven dependencies for CVE-2026-33012?
Run the dependency tree command: 'mvn dependency:tree -Dincludes=io.micronaut'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-2hcp-gjrf-7fhc",
  "modified" : "2026-03-20T21:21:54Z",
  "published" : "2026-03-17T18:39:27Z",
  "aliases" : [ "CVE-2026-33012" ],
  "summary" : "Micronaut Framework vulnerable to a Denial of Service in HTML error response caching",
  "details" : "`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\nto cause a denial of service (unbounded heap growth and OutOfMemoryError). \n\nFixed via: https://github.com/micronaut-projects/micronaut-core/commit/1e2ba2c14386af3d47751732d02053a72b0b49b3",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Maven",
      "name" : "io.micronaut:micronaut-http-server"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "4.7.0"
      }, {
        "fixed" : "4.10.17"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/micronaut-projects/micronaut-core/security/advisories/GHSA-2hcp-gjrf-7fhc"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-33012"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/micronaut-projects/micronaut-core/commit/1e2ba2c14386af3d47751732d02053a72b0b49b3"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/micronaut-projects/micronaut-core"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/micronaut-projects/micronaut-core/releases/tag/v4.10.17"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-770" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-03-17T18:39:27Z",
    "nvd_published_at" : "2026-03-20T05:16:15Z"
  }
}