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Fencer Vulns
medium 5.5

CVE-2023-2422 json

Keycloak: oauth client impersonation

published 2023-06-30 3 y ago modified 2026-06-17 4 mo ago also GHSA-3qh5-qqj2-c78f , EUVD-2023-1672

cvss
5.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.5%
EPSS 0.5% chance of exploitation in 30 days, percentile 44%
public exploits
0
none known

Summary

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.

Patch / fix

  • maven org.keycloak:keycloak-services 21.1.2
  • Red Hat Red Hat Single Sign-On 7.6 for RHEL 7 0:18.0.8-1.redhat_00001.1.el7sso
  • Red Hat Red Hat Single Sign-On 7.6 for RHEL 8 0:18.0.8-1.redhat_00001.1.el8sso
  • Red Hat Red Hat Single Sign-On 7.6 for RHEL 9 0:18.0.8-1.redhat_00001.1.el9sso
  • Red Hat RHEL-8 based Middleware Containers 7.6-24
  • rh-sso7-keycloak red hat single sign on 7.6 18.0.8-1.redhat_00001.1.el9sso
  • rh-sso7-keycloak-server red hat single sign on 7.6 18.0.8-1.redhat_00001.1.el9sso
  • rh-sso7-keycloak red hat single sign on 7.6 18.0.8-1.redhat_00001.1.el8sso
  • rh-sso7-keycloak-server red hat single sign on 7.6 18.0.8-1.redhat_00001.1.el8sso
  • rh-sso7-keycloak red hat single sign on 7.6 18.0.8-1.redhat_00001.1.el7sso
  • rh-sso7-keycloak-server red hat single sign on 7.6 18.0.8-1.redhat_00001.1.el7sso

red hat advisories RHSA-2023:3885RHSA-2023:3884RHSA-2023:3883

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2023-2422 updated cvss 5.5

keycloak: oauth client impersonation

  • Red Hat Middleware Containers for OpenShift rh-sso-7/sso76-openshift-rhel8 7.6-24
    fixed: vendor fix RHSA-2023:3888
  • Red Hat Single Sign-On 7
    fixed: vendor fix RHSA-2023:3892
  • Red Hat Single Sign-On 7.6 for RHEL 7 Server rh-sso7-keycloak 18.0.8-1.redhat_00001.1.el7sso, rh-sso7-keycloak-server 18.0.8-1.redhat_00001.1.el7sso
    fixed: vendor fix RHSA-2023:3883
  • Red Hat Single Sign-On 7.6 for RHEL 8 rh-sso7-keycloak 18.0.8-1.redhat_00001.1.el8sso, rh-sso7-keycloak-server 18.0.8-1.redhat_00001.1.el8sso
    fixed: vendor fix RHSA-2023:3884
  • Red Hat Single Sign-On 7.6 for RHEL 9 rh-sso7-keycloak 18.0.8-1.redhat_00001.1.el9sso, rh-sso7-keycloak-server 18.0.8-1.redhat_00001.1.el9sso
    fixed: vendor fix RHSA-2023:3885

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
2 y ago

Exploit prediction

0.52% chance of exploitation in the next 30 days, higher than 44% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 5.5 CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:L/A:N
NVD 3.1 7.1 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N
GitHub 3.1 7.1 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N

Affected packages

ecosystem package affected fixed in
maven org.keycloak:keycloak-services
<21.1.2
21.1.2

Affected products

  • Red Hat Red Hat Single Sign-On 7
  • Red Hat Red Hat Single Sign-On 7.6 for RHEL 7
  • Red Hat Red Hat Single Sign-On 7.6 for RHEL 8
  • Red Hat Red Hat Single Sign-On 7.6 for RHEL 9
  • Red Hat RHEL-8 based Middleware Containers

Classification

Weakness
  • CWE-295 Improper Certificate Validation

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.