CVE-2023-6841: Keycloak core Denial of Service Vulnerability

HIGH
Advisory Identifier: GHSA-w97f-w3hq-36g2
Share
CVSS 6.5
CWE-231
Published
Advisory Summary

CVE-2023-6841 is a HIGH (CVSS 6.5) denial of service vulnerability (CWE-231: Improper Handling of Extra Values) affecting Keycloak core libraries in the Maven ecosystem. The issue involves keycloak denial of service vulnerability. Remediation is available by upgrading affected packages to version 24.0.0.

CVE-2023-6841 at a Glance

CVE Identifier CVE-2023-6841
GHSA Identifier GHSA-w97f-w3hq-36g2
Severity HIGH
CVSS v3.1 Base Score 6.5
CWE Classification CWE-231: Improper Handling of Extra Values
Affected Product Keycloak core
Package Ecosystem Maven
Published Date
Last Updated

Security Impact

CVSS: 6.5

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

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required Low (PR:L)
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-2023-6841

To remediate this vulnerability, upgrade all affected Keycloak core 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-core fixed: 24.0.0 
<dependency>
    <groupId>org.keycloak</groupId>
    <artifactId>keycloak-core</artifactId>
    <version>24.0.0</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-2023-6841, 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 core in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 24.0.0), 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-231: Improper Handling of Extra Values, where the product does not handle or incorrectly handles when more values are provided than expected. In Keycloak core, 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 denial of service vulnerability was found in keycloak where the amount of attributes per object is not limited, an attacker by sending repeated HTTP requests could cause a resource exhaustion when the application send back rows with long attribute values. The issue is fixed in Keycloak 24 with the introduction of the User Profile feature.

CVE-2023-6841 Affected Keycloak core Versions

1 component(s)
Fixed Versions:
24.0.0
Product / Package Ecosystem Affected Versions Fixed Version
org.keycloak:keycloak-core
maven/org.keycloak/keycloak-core
Maven
< 24.0.0
24.0.0

References

NVD — CVE-2023-6841 NVD
https://nvd.nist.gov/vuln/detail/CVE-2023-6841
Keycloak core Source Repository REPOSITORY
https://github.com/keycloak/keycloak/issues/32837
Keycloak core Security Information SECURITY
https://access.redhat.com/security/cve/CVE-2023-6841
bugzilla.redhat.com/show_bug.cgi WEB
https://bugzilla.redhat.com/show_bug.cgi?id=2254714
Keycloak core Source Repository REPOSITORY
https://github.com/keycloak/keycloak
Keycloak core Release RELEASE
https://github.com/keycloak/keycloak/releases/tag/24.0.0

Frequently Asked Questions

What is CVE-2023-6841?
CVE-2023-6841 is a security vulnerability in Keycloak core involving Keycloak Denial of Service vulnerability under CWE-231: Improper Handling of Extra Values.
Which Keycloak core versions are affected?
Affected versions include releases prior to 24.0.0 across affected packages: org.keycloak:keycloak-core.
What version fixes CVE-2023-6841?
Upgrading to 24.0.0 (or the latest patched release for your respective branch) resolves the vulnerability.
Is keycloak-core affected?
Yes, org.keycloak:keycloak-core is affected in releases prior to 24.0.0. Upgrade your dependency to 24.0.0 or later.
What is the CVSS score of CVE-2023-6841?
CVE-2023-6841 has a CVSS v3.1 base score of 6.5 (HIGH) with vector string CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H.
What CWE is associated with CVE-2023-6841?
CVE-2023-6841 is classified under CWE-231: Improper Handling of Extra Values (The product does not handle or incorrectly handles when more values are provided than expected.).
How can I check Maven dependencies for CVE-2023-6841?
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-w97f-w3hq-36g2",
  "modified" : "2024-11-18T16:27:11Z",
  "published" : "2024-09-10T18:30:44Z",
  "aliases" : [ "CVE-2023-6841" ],
  "summary" : "Keycloak Denial of Service vulnerability",
  "details" : "A denial of service vulnerability was found in keycloak where the amount of attributes per object is not limited, an attacker by sending repeated HTTP requests could cause a resource exhaustion when the application send back rows with long attribute values. The issue is fixed in Keycloak 24 with the introduction of the User Profile feature.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"
  }, {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Maven",
      "name" : "org.keycloak:keycloak-core"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "24.0.0"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2023-6841"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/keycloak/keycloak/issues/32837"
  }, {
    "type" : "WEB",
    "url" : "https://access.redhat.com/security/cve/CVE-2023-6841"
  }, {
    "type" : "WEB",
    "url" : "https://bugzilla.redhat.com/show_bug.cgi?id=2254714"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/keycloak/keycloak"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/keycloak/keycloak/releases/tag/24.0.0"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-231" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2024-09-10T19:41:54Z",
    "nvd_published_at" : "2024-09-10T17:15:15Z"
  }
}