Description
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.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| 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 | — | — |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Red Hat Single Sign On 7 | rh-sso7-keycloak +1 | 18.0.8-1.redhat_00001.1.el7sso | RHSA-2023:3885, RHSA-2023:3884, RHSA-2023:3883 |
Affected packages
| Ecosystem | Package | Affected | Fixed | Record |
|---|---|---|---|---|
| Maven | org.keycloak:keycloak-services | < 21.1.2 | 21.1.2 | GHSA-3qh5-qqj2-c78f |
Advisories 4
- RHSA-2023:3885 Red Hat Security Advisory: Red Hat Single Sign-On 7.6.4 security update on RHEL 9 Red Hat Security Advisories (RHSA) · Oct 2, 2026
- RHSA-2023:3883 Red Hat Security Advisory: Red Hat Single Sign-On 7.6.4 security update on RHEL 7 Red Hat Security Advisories (RHSA) · Oct 2, 2026
- RHSA-2023:3884 Red Hat Security Advisory: Red Hat Single Sign-On 7.6.4 security update on RHEL 8 Red Hat Security Advisories (RHSA) · Oct 2, 2026
- WID-SEC-2023-1573 Keycloak: Mehrere Schwachstellen ermöglichen Umgehen von Sicherheitsvorkehrungen BSI CERT-Bund (WID) · Jun 27, 2023
References
- RHSA-2023:3883 vendor-advisory
- RHSA-2023:3884 vendor-advisory
- RHSA-2023:3885 vendor-advisory
- RHSA-2023:3888 vendor-advisory
- RHSA-2023:3892 vendor-advisory
- https://access.redhat.com/security/cve/CVE-2023-2422 vdb-entry
- RHBZ#2191668 issue-tracking