Description
An unconstrained memory consumption vulnerability was discovered in Keycloak. It can be triggered in environments which have millions of offline tokens (> 500,000 users with each having at least 2 saved sessions). If an attacker creates two or more user sessions and then open the "consents" tab of the admin User Interface, the UI attempts to load a huge number of offline client sessions leading to excessive memory and CPU consumption which could potentially crash the entire system.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| 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 | — | — |
| Red Hat | Single Sign-On 7.6.6 | — | — |
| Red Hat | Red Hat Build of Keycloak | — | — |
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 | 18.0.11-2.redhat_00003.1.el7sso | RHSA-2023:7856, RHSA-2023:7855, RHSA-2023:7854 |
Affected packages
| Ecosystem | Package | Affected | Fixed | Record |
|---|---|---|---|---|
| Maven | org.keycloak:keycloak-model-jpa | < 21.0.0 | 21.0.0 | GHSA-54f3-c6hg-865h |
Advisories 4
- RHSA-2023:7856 Red Hat Security Advisory: Red Hat Single Sign-On 7.6.6 security update on RHEL 8 Red Hat Security Advisories (RHSA) · Sep 22, 2026
- RHSA-2023:7854 Red Hat Security Advisory: Red Hat Single Sign-On 7.6.6 security update on RHEL 7 Red Hat Security Advisories (RHSA) · Sep 22, 2026
- RHSA-2023:7855 Red Hat Security Advisory: Red Hat Single Sign-On 7.6.6 security update on RHEL 9 Red Hat Security Advisories (RHSA) · Sep 22, 2026
- WID-SEC-2023-3156 Keycloak: Mehrere Schwachstellen BSI CERT-Bund (WID) · Jul 1, 2024
References
- RHSA-2023:7854 vendor-advisory
- RHSA-2023:7855 vendor-advisory
- RHSA-2023:7856 vendor-advisory
- RHSA-2023:7857 vendor-advisory
- RHSA-2023:7858 vendor-advisory
- https://access.redhat.com/security/cve/CVE-2023-6563 vdb-entry
- RHBZ#2253308 issue-tracking
- https://github.com/keycloak/keycloak/issues/13340