Description
A flaw was found in the user-event metrics recording of Keycloak. When metrics are enabled, the system records raw error messages from failed account operations as Prometheus metric labels. Because these error messages can include user-supplied input like nonexistent client IDs, an authenticated user can create a massive number of unique metric entries, eventually exhausting system memory and causing the service to crash or become unavailable.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Red Hat | Red Hat build of Keycloak 26.6 | — | — |
| Red Hat | Red Hat build of Keycloak 26.6.5 | — | — |
| Red Hat | Red Hat Data Grid 8 | — | — |
| Red Hat | Red Hat JBoss Enterprise Application Platform Expansion Pack | — | — |
| Red Hat | Red Hat Single Sign-On 7 | — | — |
Advisories 1
- WID-SEC-2026-2677 RedHat Build of Keycloak: Mehrere Schwachstellen BSI CERT-Bund (WID) · Nov 5, 2026
References
- RHSA-2026:50848 vendor-advisory
- RHSA-2026:50849 vendor-advisory
- https://access.redhat.com/security/cve/CVE-2026-16100 vdb-entry
- RHBZ#2501730 issue-tracking