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.

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Fixes

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Workaround

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History

Wed, 27 May 2026 15:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Wed, 27 May 2026 12:45:00 +0000

Type Values Removed Values Added
First Time appeared Redhat build Of Keycloak
Vendors & Products Redhat build Of Keycloak

Wed, 27 May 2026 11:45:00 +0000

Type Values Removed Values Added
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.
Title Keycloak: org.keycloak.protocol.oidc: http parameter pollution in oidc redirect uri allows response parameter duplication - #ghi-604
First Time appeared Redhat
Redhat build Keycloak
Weaknesses CWE-1288
CPEs cpe:/a:redhat:build_keycloak:
Vendors & Products Redhat
Redhat build Keycloak
References
Metrics cvssV3_1

{'score': 4.2, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:N'}


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cve-icon MITRE

Status: PUBLISHED

Assigner: redhat

Published:

Updated: 2026-05-27T14:46:20.866Z

Reserved: 2026-05-27T10:14:17.955Z

Link: CVE-2026-9689

cve-icon Vulnrichment

Updated: 2026-05-27T14:46:04.250Z

cve-icon NVD

Status : Awaiting Analysis

Published: 2026-05-27T12:17:15.513

Modified: 2026-05-27T14:54:20.160

Link: CVE-2026-9689

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-05-27T12:30:25Z

Weaknesses