CVE-2026-16100
Keycloak-services: keycloak-services: unbounded metric cardinality in user event metrics via request-controlled error text
CVSS Score
6.5
EPSS Score
0.0%
EPSS Percentile
0th
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.
| Vendor | red hat |
| Product | red hat build of keycloak |
| Published | Aug 5, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H Attack Vector
Network
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High
Affected Versions
Red Hat / Red Hat Build of Keycloak
All versions affected Red Hat / Red Hat Build of Keycloak
All versions affected Red Hat / Red Hat Build of Keycloak
All versions affected Red Hat / Red Hat Data Grid 8
All versions affected Red Hat / Red Hat JBoss Enterprise Application Platform Expansion Pack
All versions affected Red Hat / Red Hat Single Sign-On 7
All versions affected References
Credits
Red Hat would like to thank Paul Bottinelli (Trail of Bits) for reporting this issue.