CVE-2023-6563

Keycloak: offline session token dos

Published Dec 14, 2023 CVSS 3.1 · 7.7 High EPSS 1.2% KEV · Not listed
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.

Remediation

Vendor Workaround

There are three main options to prevent exploitation: 1) If you are using a reverse proxy, block the consents URL. 2) This option is less effective: remove the consents application tab from the account console theme. 3) This option has a significant negative impact on end users: entirely disable offline user profiles.

Tracking

Sign in to view the affected projects.

Advisories

Source ID Title
EUVD EUVD EUVD-2023-3108 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.
Github GHSA Github GHSA GHSA-54f3-c6hg-865h Allocation of Resources Without Limits in Keycloak
History
Type Values Removed Values Added
CPEs cpe:/a:redhat:red_hat_single_sign_on:7.6
Type Values Removed Values Added
CPEs cpe:/a:redhat:build_keycloak:22 cpe:/a:redhat:build_keycloak: