CVE-2026-4634highCWE-1050

CVE-2026-4634: high-severity vulnerability in Red Hat build of Keycloak 26.2

Keycloak: keycloak: denial of service via excessive processing of openid connect scope parameters

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21Vexday Risk Score

No sign of exploitation. No public exploitation artifact known so far.

ssvc Trackcvss 7.5epss 0.6%
A flaw was found in Keycloak. An unauthenticated attacker can exploit this vulnerability by sending a specially crafted POST request with an excessively long scope parameter to the OpenID Connect (OIDC) token endpoint. This leads to high resource consumption and prolonged processing times, ultimately resulting in a Denial of Service (DoS) for the Keycloak server.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Affected products
Red Hat · Red Hat build of Keycloak 26.2Red Hat · Red Hat build of Keycloak 26.2.15Red Hat · Red Hat build of Keycloak 26.4Red Hat · Red Hat build of Keycloak 26.4.11Red Hat · Red Hat Single Sign-On 7.6.13Red Hat · Red Hat Single Sign-On 7.6 for RHEL 7Red Hat · Red Hat Single Sign-On 7.6 for RHEL 8Red Hat · Red Hat Single Sign-On 7.6 for RHEL 9Red Hat · RHEL-8 based Middleware Containers
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