CVE-2026-101333 Keycloak-services: keycloak-services: unbounded metric series creation via idp tag on broker login endpoint
An unauthenticated attacker can cause excessive memory consumption and degrade performance by sending arbitrary requests to the broker login endpoint when specific metrics are enabled.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-101333?
CVE-2026-101333 is a low-severity denial of service vulnerability in Red Hat Build of Keycloak, published on 28 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
A flaw was found in the Micrometer user-event metrics listener of Keycloak, a solution for integrated identity and access management. The issue occurs when the listener is configured to include the idp tag. An unauthenticated attacker can send requests to the identity broker login endpoint using arbitrary provider aliases, causing the system to create an unlimited number of metric time series. This can lead to excessive memory consumption and degrade the performance of both the server and its monitoring tools.
Weakness: CWE-770
Which versions are affected by CVE-2026-101333?
How do I fix CVE-2026-101333?
No fix has been published for CVE-2026-101333 yet. Limit exposure of the affected software until one is available.
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-2026-101333 being exploited?
There is no known exploitation of CVE-2026-101333 in the wild and no public exploit code.
Sources
Also known as GHSA-5fh4-qp8q-2wxm, UBUNTU-CVE-2026-101333.