CVE-2026-79651 Keycloak-services: keycloak-services: unauthenticated dos via unbounded locale caching
Unauthenticated attackers can crash the Keycloak server by exhausting memory through unbounded locale caching in theme endpoints.
- 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-2026-79651?
CVE-2026-79651 is a high-severity denial of service vulnerability in Red Hat Single Sign-On 7, published on 16 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 theme localization endpoints of the keycloak-services component, which is the core service responsible for authentication flows and theme management in Keycloak. The issue occurs because the system accepts arbitrary locale tags from unauthenticated requests and stores them in a permanent in-memory cache without limits. An attacker can exploit this by sending a large number of unique locale tags, eventually causing the server to run out of memory and crash.
Weakness: CWE-400
Which versions are affected by CVE-2026-79651?
How do I fix CVE-2026-79651?
No fix has been published for CVE-2026-79651 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-2026-79651 being exploited?
There is no known exploitation of CVE-2026-79651 in the wild and no public exploit code.
Sources
Also known as GHSA-8qv5-pjhw-3gx4.