CVE-2026-4634
Fixed in a distro release EPSS <1%CVSS 7.5
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.
Products: Red Hat build of Keycloak 26.2, Red Hat build of Keycloak 26.2.15, Red Hat build of Keycloak 26.4, Red Hat build of Keycloak 26.4.11, Red Hat Single Sign-On 7.6.13, Red Hat Single Sign-On 7.6 for RHEL 7, Red Hat Single Sign-On 7.6 for RHEL 8, Red Hat Single Sign-On 7.6 for RHEL 9, Red Hat RHEL-8 based Middleware Containers
Fixed upstream
| Ecosystem | Package | Fixed in |
|---|---|---|
| Maven | org.keycloak:keycloak-services | 26.5.7 |
Distro releases
| Release | Package | Fixed in |
|---|---|---|
| Chainguard | keycloak-26.3-iamguarded-compat | no fix |
| Chainguard | keycloak-26.4 | no fix |
| Chainguard | keycloak-26.4-iamguarded-compat | no fix |
| Chainguard | keycloak-26.5 | 26.5.7-r0 |
| Chainguard | keycloak-26.5-iamguarded-compat | 26.5.7-r0 |
| Chainguard | keycloak-fips-26.3-iamguarded-fips | no fix |
| Chainguard | keycloak-fips-26.4 | no fix |
| Chainguard | keycloak-fips-26.4-iamguarded-fips | no fix |
| Chainguard | keycloak-fips-26.5 | 26.5.6-r4 |
| Chainguard | keycloak-fips-26.5-iamguarded-fips | 26.5.6-r4 |
| Chainguard | request-9047-keycloak-fips-26.4 | no fix |
| Chainguard | request-9047-keycloak-fips-26.4-iamguarded-fips | no fix |
| Red Hat red hat single sign on 7.6 | rh-sso7-keycloak | 0:18.0.20-1.redhat_00001.1.el8sso |
| Red Hat red hat single sign on 7.6 | rh-sso7-keycloak | 0:18.0.20-1.redhat_00001.1.el9sso |
| Red Hat red hat single sign on 7.6 | rh-sso7-keycloak | 0:18.0.20-1.redhat_00001.1.el7sso |
| Red Hat red hat single sign on 7.6 | rh-sso7-keycloak-server | 0:18.0.20-1.redhat_00001.1.el9sso |
| Red Hat red hat single sign on 7.6 | rh-sso7-keycloak-server | 0:18.0.20-1.redhat_00001.1.el8sso |
| Red Hat red hat single sign on 7.6 | rh-sso7-keycloak-server | 0:18.0.20-1.redhat_00001.1.el7sso |
| Wolfi | keycloak-26.4 | no fix |
| Wolfi | keycloak-26.4-iamguarded-compat | no fix |
| Wolfi | keycloak-26.5 | 26.5.7-r0 |
| Wolfi | keycloak-26.5-iamguarded-compat | 26.5.7-r0 |