Resource exhaustion in Keycloak - CVE-2026-79651
Published: September 18, 2026
Vulnerability identifier: #VU150835
CSH Severity: Medium
CVSS v4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-79651
CWE-ID: CWE-400
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to cause a denial of service.
The vulnerability exists due to uncontrolled resource consumption in the theme localization endpoints of the keycloak-services component when processing unauthenticated requests containing arbitrary locale tags. A remote attacker can send a large number of unique locale tags to exhaust memory and cause a denial of service.
The supplied locale tags are stored in a permanent in-memory cache without limits.
Affected software
Keycloak
How to mitigate CVE-2026-79651
Install security update from vendor's website.
Keycloak - update to 26.7.4