CVE-2023-6563: Keycloak: offline session token dos

Vulnerability summary

CVE-2023-6563 is a high (CVSS 7.7) vulnerability in redhat keycloak. EPSS estimates a 1.24% chance of exploitation in the next 30 days, higher than 69.1% of scored vulnerabilities. 1 public exploit is recorded.

Timeline

1. 14-12-2023
   PublishedVulnerability first disclosed.
2. 22-09-2026
   Last modifiedVulnerability information updated.

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.

• CWE-770Allocation of Resources Without Limits or ThrottlingThe product allocates a reusable resource or group of resources on behalf of an actor without imposing any intended restrictions on the size or number of resources that can be allocated.