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CVE-2023-2422

Keycloak: oauth client impersonation

5.5 MediumFix available

A flaw was found in Keycloak. A Keycloak server configured to support mTLS authentication for OAuth/OpenID clients does not properly verify the client certificate chain. A client that possesses a proper certificate can authorize itself as any other client, therefore, access data that belongs to other clients.

Attack profile

How easy it is to exploit

Attack vector
Network
Complexity
Low
Privileges needed
High
User interaction
None

What an attacker can affect

Confidentiality
High
Integrity
Low
Availability
None

Exploit likelihood

0.52%Up 0.5 points since Oct 5, 2023
90%50%10%1%

What each source reports

CVE List Score used 5.5

Keycloak: oauth client impersonation

A flaw was found in Keycloak. A Keycloak server configured to support mTLS authentication for OAuth/OpenID clients does not properly verify the client certificate chain. A client that possesses a proper certificate can authorize itself as any other client, therefore, access data that belongs to other clients.

Record
CVE-2023-2422
CVSS 3.1
5.5 MediumCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:L/A:N
Weakness
CWE-295
Updated
2026-11-02
EUVDEUVD-2023-1672 5.5

A flaw was found in Keycloak. A Keycloak server configured to support mTLS authentication for OAuth/OpenID clients does not properly verify the client certificate chain. A client that possesses a proper certificate can authorize itself as any other client, therefore, access data that belongs to other clients.

Record
EUVD-2023-1672
CVSS 3.1
5.5 MediumCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:L/A:N
Updated
2026-11-03
GitHub AdvisoriesGHSA-3qh5-qqj2-c78f 7.1

Keycloak vulnerable to Improper Client Certificate Validation for OAuth/OpenID clients

When a Keycloak server is configured to support mTLS authentication for OAuth/OpenID clients, it does not properly verify the client certificate chain. A client that possesses a proper certificate can authorize itself as any other client and therefore access data that belongs to other clients.

Record
GHSA-3qh5-qqj2-c78f
CVSS 3.1
7.1 HighCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N
Weakness
CWE-295
Updated
2026-11-02
NVD 5.5

A flaw was found in Keycloak. A Keycloak server configured to support mTLS authentication for OAuth/OpenID clients does not properly verify the client certificate chain. A client that possesses a proper certificate can authorize itself as any other client, therefore, access data that belongs to other clients.

Record
CVE-2023-2422
CVSS 3.1
5.5 MediumCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:L/A:N
CVSS 3.1
7.1 HighCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N
Weakness
CWE-295
Updated
2026-11-02
OSVGHSA-3qh5-qqj2-c78f 7.1

Keycloak vulnerable to Improper Client Certificate Validation for OAuth/OpenID clients

When a Keycloak server is configured to support mTLS authentication for OAuth/OpenID clients, it does not properly verify the client certificate chain. A client that possesses a proper certificate can authorize itself as any other client and therefore access data that belongs to other clients.

Record
GHSA-3qh5-qqj2-c78f
CVSS 3.1
7.1 HighCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N
Weakness
CWE-295
Updated
2026-11-02
OSVRHSA-2023:3883 8.1

Red Hat Security Advisory: Red Hat Single Sign-On 7.6.4 security update on RHEL 7

Record
RHSA-2023:3883
CVSS 3.1
8.1 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N
Updated
2026-11-02
OSVRHSA-2023:3884 8.1

Red Hat Security Advisory: Red Hat Single Sign-On 7.6.4 security update on RHEL 8

Record
RHSA-2023:3884
CVSS 3.1
8.1 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N
Updated
2026-11-02
OSVRHSA-2023:3885 8.1

Red Hat Security Advisory: Red Hat Single Sign-On 7.6.4 security update on RHEL 9

Record
RHSA-2023:3885
CVSS 3.1
8.1 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N
Updated
2026-11-02

Affected products

Affected packages

Affected packages
PackageAffectedFixed
org.keycloak:keycloak-services
Maven
 before 21.1.2
21.1.2
org.keycloak:keycloak-services
Maven
 before 21.1.2, plus listed versions
1.0-alpha-11.0-alpha-1-120620131.0-alpha-21.0-alpha-31.0-alpha-4
Show 45 moreShow less
1.0-beta-11.0-beta-1-201505211.0-beta-1-201505231.0-beta-21.0-beta-31.0-beta-41.0-final1.0-rc-11.0-rc-21.0.1.Final1.0.2.Final1.0.3.Final1.0.4.Final1.0.5.Final1.1.0.Beta11.1.0.Beta21.1.0.Final1.1.1.Final1.2.0.Beta11.2.0.CR11.2.0.Final1.3.0.Final1.3.1.Final1.4.0.Final1.5.0-Final1.5.0.Final1.5.1.Final1.6.0.Final1.6.1.Final1.7.0.CR11.7.0.Final1.8.0.Alpha11.8.0.CR11.8.0.CR21.8.0.CR31.8.0.Final1.8.1.Final1.9.0.CR11.9.0.Final1.9.1.Final1.9.2.Final1.9.3.Final1.9.4.Final1.9.5.Final1.9.7.Final
21.1.2
rh-sso7-keycloak
Red Hat:red_hat_single_sign_on:7.6::el7
From an advisory covering 5 CVEs
 before 0:18.0.8-1.redhat_00001.1.el7sso
0:18.0.8-1.redhat_00001.1.el7sso
rh-sso7-keycloak-server
Red Hat:red_hat_single_sign_on:7.6::el7
From an advisory covering 5 CVEs
 before 0:18.0.8-1.redhat_00001.1.el7sso
0:18.0.8-1.redhat_00001.1.el7sso
rh-sso7-keycloak
Red Hat:red_hat_single_sign_on:7.6::el8
From an advisory covering 5 CVEs
 before 0:18.0.8-1.redhat_00001.1.el8sso
0:18.0.8-1.redhat_00001.1.el8sso
rh-sso7-keycloak-server
Red Hat:red_hat_single_sign_on:7.6::el8
From an advisory covering 5 CVEs
 before 0:18.0.8-1.redhat_00001.1.el8sso
0:18.0.8-1.redhat_00001.1.el8sso
rh-sso7-keycloak
Red Hat:red_hat_single_sign_on:7.6::el9
From an advisory covering 5 CVEs
 before 0:18.0.8-1.redhat_00001.1.el9sso
0:18.0.8-1.redhat_00001.1.el9sso
rh-sso7-keycloak-server
Red Hat:red_hat_single_sign_on:7.6::el9
From an advisory covering 5 CVEs
 before 0:18.0.8-1.redhat_00001.1.el9sso
0:18.0.8-1.redhat_00001.1.el9sso

History

History
RecordedChangedSources
affected, facts
aliasesEUVD
first indexedCVE List, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2023-2422 is a medium vulnerability (CVSS 5.5) in Redhat Keycloak, published June 30, 2023. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.52%, the 44th percentile. Fixed in org.keycloak:keycloak-services 21.1.2.

References

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Left out here: 103 versions. The JSON record has them.

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