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.
Published: 2026-08-05
Score: 6.5 Medium
EPSS: < 1% Very Low
KEV: No
Impact: n/a
Action: n/a
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Remediation

Vendor Workaround

Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.

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History

Fri, 07 Aug 2026 10:30:00 +0000

Type Values Removed Values Added
First Time appeared Redhat build Of Keycloak
Redhat data Grid 8
Redhat jboss Enterprise Application Platform Expansion Pack
Redhat single Sign On
Vendors & Products Redhat build Of Keycloak
Redhat data Grid 8
Redhat jboss Enterprise Application Platform Expansion Pack
Redhat single Sign On

Thu, 06 Aug 2026 00:15:00 +0000

Type Values Removed Values Added
References
Metrics threat_severity

None

threat_severity

Moderate


Wed, 05 Aug 2026 20:15:00 +0000

Type Values Removed Values Added
Weaknesses CWE-400

Wed, 05 Aug 2026 18:30:00 +0000

Type Values Removed Values Added
Weaknesses CWE-770
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Wed, 05 Aug 2026 17:00:00 +0000

Type Values Removed Values Added
CPEs cpe:/a:redhat:build_keycloak: cpe:/a:redhat:build_keycloak:26.6::el9
References

Wed, 05 Aug 2026 16:15:00 +0000

Type Values Removed Values Added
Weaknesses CWE-400

Wed, 05 Aug 2026 14:45:00 +0000

Type Values Removed Values Added
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.
Title Keycloak-services: keycloak-services: unbounded metric cardinality in user event metrics via request-controlled error text
First Time appeared Redhat
Redhat build Keycloak
Redhat jboss Data Grid
Redhat jbosseapxp
Redhat red Hat Single Sign On
CPEs cpe:/a:redhat:build_keycloak:
cpe:/a:redhat:jboss_data_grid:8
cpe:/a:redhat:jbosseapxp
cpe:/a:redhat:red_hat_single_sign_on:7
Vendors & Products Redhat
Redhat build Keycloak
Redhat jboss Data Grid
Redhat jbosseapxp
Redhat red Hat Single Sign On
References
Metrics cvssV3_1

{'score': 6.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'}


Subscriptions

Redhat Build Keycloak Build Of Keycloak Data Grid 8 Jboss Data Grid Jboss Enterprise Application Platform Expansion Pack Jbosseapxp Red Hat Single Sign On Single Sign On
cve-icon MITRE

Status: PUBLISHED

Assigner: redhat

Published:

Updated: 2026-08-05T18:45:38.602Z

Reserved: 2026-07-17T14:26:03.169Z

Link: CVE-2026-16100

cve-icon Vulnrichment

Updated: 2026-08-05T17:38:13.432Z

cve-icon NVD

No data.

cve-icon Redhat

Severity : Moderate

Publid Date: 2026-08-05T02:02:00Z

Links: CVE-2026-16100 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-08-07T10:06:22Z

Weaknesses