CVE-2026-16100 — Keycloak-services: keycloak-services: unbounded metric cardinality in user event metrics via request-controlled error text
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 me…
Published: 2026-08-05 · CVSS: 6.5 · CVSS 3.1
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.
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7