CVE-2026-9689 Keycloak Services has Improper Validation of Consistency within Input
Attackers can bypass security measures and gain unauthorized access via HTTP parameter pollution in OIDC redirect URIs when broad URIs are configured.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-9689?
CVE-2026-9689 is a medium-severity authentication bypass vulnerability in Redhat Build of Keycloak, published on 27 May 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official description
A flaw was found in Keycloak, an open-source identity and access management solution. When a client application is configured to accept broad redirect Uniform Resource Identifiers (URIs), a remote attacker can manipulate the authentication process by crafting a special web address. If a user clicks this link, the client application might incorrectly prioritize attacker-controlled information over legitimate data. This vulnerability, known as HTTP parameter pollution, could allow an attacker to bypass security measures or gain unauthorized access to resources.
Weakness: CWE-1288
Which versions are affected by CVE-2026-9689?
4 open source packages ship an affected version, including org.keycloak:keycloak-services. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
org.keycloak:keycloak-services Maven | All versions to 26.4.7 | None |
org.keycloak:keycloak-services Maven | All versions to 26.4.7 | None |
org.keycloak:keycloak-services Maven | From 26.5.0 to 26.6.4 | None |
org.keycloak:keycloak-services Maven | From 26.5.0 to 26.6.4 | None |
Products include Redhat Build of Keycloak.
How do I fix CVE-2026-9689?
Upgrade to a fixed version.
Upgrade, and rotate credentials and sessions that may have been exposed. More about Authentication bypass.
Is CVE-2026-9689 being exploited?
There is no known exploitation of CVE-2026-9689 in the wild and no public exploit code.
Other vulnerabilities in Redhat Build of Keycloak
- CVE-2026-15572 Keycloak-services: keycloak-services: dcr protocol mapper type-swap policy bypass allows privilege escalation
- CVE-2026-3047 Keycloak SAML Broken has Authentication Bypass by Primary Weakness
- CVE-2026-15573 Keycloak-services: keycloak-services: authorization bypass via unnormalized uri matching in pathmatcher
- CVE-2026-16102 Keycloak-services: keycloak-services: default dcr policy allows role forgery via user property mappers
- CVE-2026-1609 Org.keycloak/keycloak-quarkus-server: keycloak: unauthorized access via jwt authorization grant with disabled users
Sources
Also known as ECHO-6280-5637-dd2f, GHSA-wcvj-vpvw-9rr5, MINI-78hg-7xf7-9cj7, MINI-7r7v-98hv-q3jv.