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Vulnerability · Published Sep 16, 2026 · Assigned by redhat

CVE-2026-79651Keycloak-services: keycloak-services: unauthenticated dos via unbounded locale caching

High 7.5

In plain English

A high-severity uncontrolled resource consumption in Red Hat build of Keycloak 26.4 from Red Hat. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.8% (higher than 57% of all known vulnerabilities).

Severity (CVSS 3.1)7.5High
Exploit odds (30 days)0.8%top 43.0% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

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.

Affected products (as reported)

VendorProductVersions
Red Hat Red Hat build of Keycloak 26.4 see references
Red Hat Red Hat build of Keycloak 26.4 see references
Red Hat Red Hat build of Keycloak 26.4 see references
Red Hat Red Hat build of Keycloak 26.4.16 see references
Red Hat Red Hat build of Keycloak 26.4.16 see references
Red Hat Red Hat build of Keycloak 26.4.16 see references
Red Hat Red Hat build of Keycloak 26.6 see references
Red Hat Red Hat build of Keycloak 26.6 see references
Red Hat Red Hat build of Keycloak 26.6 see references
Red Hat Red Hat build of Keycloak 26.6.7 see references
Red Hat Red Hat build of Keycloak 26.6.7 see references
Red Hat Red Hat build of Keycloak 26.6.7 see references
Red Hat Red Hat Single Sign-On 7 see references

Weakness: CWE-400 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

References