CVE-2026-16100: DoS (CVSS 6.5)

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.

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CVSS v3.1 Score

6.5

MEDIUM

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Weakness Type (CWE)

CWE-770 CWE-770

References

Other References

https://access.redhat.com/errata/RHSA-2026:50848 https://access.redhat.com/errata/RHSA-2026:50849 https://access.redhat.com/security/cve/CVE-2026-16100 https://bugzilla.redhat.com/show_bug.cgi?id=2501730

Frequently Asked Questions

What is CVE-2026-16100? +

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. It has a CVSS v3.1 base score of 6.5 (MEDIUM).

How severe is CVE-2026-16100? +

CVE-2026-16100 has a CVSS v3.1 score of 6.5 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance.

How do I check if I'm vulnerable to CVE-2026-16100? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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