CVE-2026-2733: Keycloak Missing Check On Disabled Client Vulnerability

LOW
Advisory Identifier: GHSA-fjf4-6f34-w64q
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CVSS 3.8
CWE-285
Published
Advisory Summary

CVE-2026-2733 is a LOW (CVSS 3.8) missing check on disabled client vulnerability (CWE-285: Improper Authorization) affecting Keycloak libraries in the Maven ecosystem. The issue involves missing check on disabled client for docker registry protocol. Remediation is available in the latest vendor maintenance releases.

CVE-2026-2733 at a Glance

CVE Identifier CVE-2026-2733
GHSA Identifier GHSA-fjf4-6f34-w64q
Severity LOW
CVSS v3.1 Base Score 3.8
CWE Classification CWE-285: Improper Authorization
Affected Product Keycloak
Package Ecosystem Maven
Published Date
Last Updated

Security Impact

CVSS: 3.8

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

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

How to Fix CVE-2026-2733

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

org.keycloak:keycloak-services fixed: Latest secure release 
<dependency>
    <groupId>org.keycloak</groupId>
    <artifactId>keycloak-services</artifactId>
    <version>Latest secure release</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=org.keycloak

How to Check if You Are Affected

To determine whether your Java application is affected by CVE-2026-2733, inspect your build dependencies using the Maven Dependency Plugin:

mvn dependency:tree -Dincludes=org.keycloak

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

Note: The mvn dependency:tree -Dincludes=org.keycloak 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-285: Improper Authorization, where the product does not perform or incorrectly performs an authorization check when an actor attempts to access a resource or perform an action. In Keycloak, 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

A flaw was identified in the Docker v2 authentication endpoint of Keycloak, where tokens continue to be issued even after a Docker registry client has been administratively disabled. This means that turning the client “Enabled” setting to OFF does not fully prevent access. As a result, previously valid credentials can still be used to obtain authentication tokens. This weakens administrative controls and could allow unintended access to container registry resources.

CVE-2026-2733 Affected Keycloak Versions

1 component(s)
Product / Package Ecosystem Affected Versions Fixed Version
org.keycloak:keycloak-services
maven/org.keycloak/keycloak-services
Maven
≤ 26.5.3

References

NVD — CVE-2026-2733 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-2733
Keycloak Source Repository REPOSITORY
https://github.com/keycloak/keycloak/issues/46462
Security Fix Commit FIX COMMIT
https://github.com/keycloak/keycloak/commit/743ac24081b2c6da36aac3775147ec5b80c2861e
access.redhat.com/errata/rhsa-2026:39... WEB
https://access.redhat.com/errata/RHSA-2026:3947
access.redhat.com/errata/rhsa-2026:39... WEB
https://access.redhat.com/errata/RHSA-2026:3948
Keycloak Security Information SECURITY
https://access.redhat.com/security/cve/CVE-2026-2733
bugzilla.redhat.com/show_bug.cgi WEB
https://bugzilla.redhat.com/show_bug.cgi?id=2440895
Keycloak Source Repository REPOSITORY
https://github.com/keycloak/keycloak

Frequently Asked Questions

What is CVE-2026-2733?
CVE-2026-2733 is a security vulnerability in Keycloak involving Missing Check on Disabled Client for Docker Registry Protocol under CWE-285: Improper Authorization.
Which Keycloak versions are affected?
Affected versions include releases prior to current release patches across affected packages: org.keycloak:keycloak-services.
What version fixes CVE-2026-2733?
Upgrading to current release patches (or the latest patched release for your respective branch) resolves the vulnerability.
Is keycloak-services affected?
Yes, org.keycloak:keycloak-services is affected in releases prior to Latest secure release. Upgrade your dependency to Latest secure release or later.
What is the CVSS score of CVE-2026-2733?
CVE-2026-2733 has a CVSS v3.1 base score of 3.8 (LOW) with vector string CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:L/I:L/A:N.
What CWE is associated with CVE-2026-2733?
CVE-2026-2733 is classified under CWE-285: Improper Authorization (The product does not perform or incorrectly performs an authorization check when an actor attempts to access a resource or perform an action.).
How can I check Maven dependencies for CVE-2026-2733?
Run the dependency tree command: 'mvn dependency:tree -Dincludes=org.keycloak'. 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-fjf4-6f34-w64q",
  "modified" : "2026-03-06T00:31:28Z",
  "published" : "2026-02-19T18:31:51Z",
  "aliases" : [ "CVE-2026-2733" ],
  "summary" : "Keycloak: Missing Check on Disabled Client for Docker Registry Protocol",
  "details" : "A flaw was identified in the Docker v2 authentication endpoint of Keycloak, where tokens continue to be issued even after a Docker registry client has been administratively disabled. This means that turning the client “Enabled” setting to OFF does not fully prevent access. As a result, previously valid credentials can still be used to obtain authentication tokens. This weakens administrative controls and could allow unintended access to container registry resources.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:L/I:L/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Maven",
      "name" : "org.keycloak:keycloak-services"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "last_affected" : "26.5.3"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-2733"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/keycloak/keycloak/issues/46462"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/keycloak/keycloak/commit/743ac24081b2c6da36aac3775147ec5b80c2861e"
  }, {
    "type" : "WEB",
    "url" : "https://access.redhat.com/errata/RHSA-2026:3947"
  }, {
    "type" : "WEB",
    "url" : "https://access.redhat.com/errata/RHSA-2026:3948"
  }, {
    "type" : "WEB",
    "url" : "https://access.redhat.com/security/cve/CVE-2026-2733"
  }, {
    "type" : "WEB",
    "url" : "https://bugzilla.redhat.com/show_bug.cgi?id=2440895"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/keycloak/keycloak"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-285" ],
    "severity" : "LOW",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-02-19T22:06:37Z",
    "nvd_published_at" : "2026-02-19T08:16:17Z"
  }
}