CVE-2026-9689
Keycloak: org.keycloak.protocol.oidc: http parameter pollution in oidc redirect uri allows response parameter duplication - #ghi-604
- State
- Published
- Severity
- 4.2 Medium
- Published
- May 27, 2026
- Updated
- Aug 20, 2026
- Reserved
- May 27, 2026
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.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 3.1 | 4.2 Medium | CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:N | redhat |
Weaknesses
- CWE-1288 Improper Validation of Consistency within Input
Affected Products
| Product | Versions |
|---|---|
Red Hat build of Keycloak 26.4Red Hat |
|
Red Hat build of Keycloak 26.4Red Hat |
|
Red Hat build of Keycloak 26.4Red Hat |
|
Red Hat build of Keycloak 26.4.14Red Hat | |
Red Hat build of Keycloak 26.6Red Hat |
|
Red Hat build of Keycloak 26.6Red Hat |
|
Red Hat build of Keycloak 26.6Red Hat |
|
Red Hat build of Keycloak 26.6.5Red Hat |
References
- RHSA-2026:50846vendor-advisory
- RHSA-2026:50847vendor-advisory
- RHSA-2026:50848vendor-advisory
- RHSA-2026:50849vendor-advisory
- https://access.redhat.com/security/cve/CVE-2026-9689vdb-entry
- RHBZ#2481845issue-tracking
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