CVE-2026-9689
Keycloak: org.keycloak.protocol.oidc: http parameter pollution in oidc redirect uri allows response parameter duplication - #ghi-604
CVSS Score
4.2
EPSS Score
0.1%
EPSS Percentile
23th
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.
| CWE | CWE-1288 |
| Vendor | red hat |
| Product | red hat build of keycloak |
| Published | May 27, 2026 |
| Last Updated | May 27, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:N Attack Vector
Network
Attack Complexity
High
Privileges Required
None
User Interaction
Required
Scope
Unchanged
Confidentiality
Low
Integrity
Low
Availability
None
Affected Versions
Red Hat / Red Hat Build of Keycloak
All versions affected References
Credits
Red Hat would like to thank Martin BartoΕ‘ for reporting this issue.