Answer in brief
CVE-2023-6563 records a High severity (CVSS 7.7) vulnerability in Keycloak: offline session token dos. The current sources do not mark it as known exploited. Affected software not mapped in the current feed; confirm the named product and version against your inventory.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 7.7. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
Affected software not mapped in the current feed; confirm the named product and version against your inventory.
| Product | Affected versions | Fixed versions |
|---|---|---|
| cpe:2.3:a:redhat:keycloak:*:*:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:a:redhat:openshift_container_platform:4.11:*:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:a:redhat:openshift_container_platform:4.12:*:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:a:redhat:openshift_container_platform_for_ibm_linuxone:4.10:*:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:a:redhat:openshift_container_platform_for_ibm_linuxone:4.9:*:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:a:redhat:openshift_container_platform_for_power:4.10:*:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:a:redhat:openshift_container_platform_for_power:4.9:*:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:a:redhat:single_sign-on:7.6:*:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:a:redhat:single_sign-on:-:*:*:*:text-only:*:*:* | Not reported | Not reported |
| cpe:2.3:o:redhat:enterprise_linux:7.0:*:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:o:redhat:enterprise_linux:9.0:*:*:*:*:*:*:* | Not reported | Not reported |
Published upstream
Dec 14, 2023
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Sep 22, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Sep 22, 2026
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.
Quoted source text, attributed separately from HOL analysis.