Keycloak: org.keycloak.protocol.oidc: http parameter pollution in oidc redirect uri allows response parameter duplication – #ghi-604_CVE-2026-9689

{
    "lastseen": "",
    "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.",
    "published": "2026-05-27T10:35:03.018Z",
    "modified": "2026-05-27T10:44:39.736Z",
    "type": "cve",
    "title": "Keycloak: org.keycloak.protocol.oidc: http parameter pollution in oidc redirect uri allows response parameter duplication - #ghi-604",
    "source": "redhat",
    "references": "https://access.redhat.com/security/cve/CVE-2026-9689\nhttps://bugzilla.redhat.com/show_bug.cgi?id=2481845",
    "id": "CVE-2026-9689",
    "bulletinFamily": "",
    "cwe": [
        "CWE-1288"
    ],
    "cvelist": null,
    "sourceData": "",
    "sourceHref": "",
    "cvss": {
        "score": 4.2,
        "severity": "MEDIUM",
        "vector": "CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:N",
        "version": "3.1"
    },
    "cvss2": [],
    "cvss3": {
        "version": "",
        "vectorString": "",
        "baseScore": 0,
        "baseSeverity": "",
        "attackVector": "",
        "attackComplexity": "",
        "privilegesRequired": "",
        "userInteraction": "",
        "scope": "",
        "confidentialityImpact": "",
        "integrityImpact": "",
        "availabilityImpact": "",
        "cvssV3": {
            "version": "",
            "vectorString": "",
            "baseScore": 0,
            "baseSeverity": "",
            "attackVector": "",
            "attackComplexity": "",
            "privilegesRequired": "",
            "userInteraction": "",
            "scope": "",
            "confidentialityImpact": "",
            "integrityImpact": "",
            "availabilityImpact": ""
        }
    },
    "href": "",
    "category_name": "CVE",
    "post_link": "",
    "product": "Red Hat Build of Keycloak",
    "version": "",
    "vendor": "Red Hat",
    "ai_description": "",
    "ai_severity": "",
    "ai_vendor": "",
    "ai_product": "",
    "ai_version": "",
    "ai_score": 0
}