CVE-2026-16100 Denial of service in Red Hat Data Grid 8
An authenticated user can cause a denial of service by exhausting memory through unbounded metric cardinality when metrics are enabled.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-16100?
CVE-2026-16100 is a medium-severity denial of service vulnerability in Redhat Build of Keycloak, published on 5 Aug 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official 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.
Weakness: CWE-770
Which versions are affected by CVE-2026-16100?
1 open source package ship an affected version, including keycloak. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
keycloak Bitnami | From 26.6.0 | 26.6.5 |
Products include Redhat Build of Keycloak.
How do I fix CVE-2026-16100?
Upgrade keycloak to 26.6.5 or later.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-16100 being exploited?
There is no known exploitation of CVE-2026-16100 in the wild and no public exploit code.
Other vulnerabilities in Redhat Build of Keycloak
- CVE-2026-15572 Keycloak-services: keycloak-services: dcr protocol mapper type-swap policy bypass allows privilege escalation
- CVE-2026-3047 Keycloak SAML Broken has Authentication Bypass by Primary Weakness
- CVE-2026-15573 Keycloak-services: keycloak-services: authorization bypass via unnormalized uri matching in pathmatcher
- CVE-2026-16102 Keycloak-services: keycloak-services: default dcr policy allows role forgery via user property mappers
- CVE-2026-1609 Org.keycloak/keycloak-quarkus-server: keycloak: unauthorized access via jwt authorization grant with disabled users
Sources
Also known as BIT-keycloak-2026-16100, GHSA-xj3w-m54w-h7p9.