CVE-2026-97174
Full vulnerability record from the local CVENow database.
Description
A flaw was found in the Client-Initiated Backchannel Authentication (CIBA) implementation of Keycloak. The CIBA endpoint fails to properly validate the sub parameter, allowing it to be stored as an additional request parameter. During the token issuance process, this injected value overwrites the legitimate subject identifier. This allows an attacker to authenticate as themselves but receive security tokens belonging to a different victim user, leading to unauthorized account access.
Severity
MEDIUM
CVSS score
6.8
(v3.1)
Vulnerability status
Awaiting Analysis
Source identifier
Published
2026-11-05 18:17:11.493000
Last modified
2026-11-05 18:17:11.630000
View original CVE JSON
{
"id": "CVE-2026-97174",
"sourceIdentifier": "[email protected]",
"published": "2026-11-05T18:17:11.493",
"lastModified": "2026-11-05T18:17:11.630",
"vulnStatus": "Awaiting Analysis",
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "A flaw was found in the Client-Initiated Backchannel Authentication (CIBA) implementation of Keycloak. The CIBA endpoint fails to properly validate the sub parameter, allowing it to be stored as an additional request parameter. During the token issuance process, this injected value overwrites the legitimate subject identifier. This allows an attacker to authenticate as themselves but receive security tokens belonging to a different victim user, leading to unauthorized account access."
}
],
"affected": [
{
"source": "[email protected]",
"affectedData": [
{
"vendor": "Red Hat",
"product": "Red Hat Build of Keycloak",
"defaultStatus": "affected",
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"packageName": "keycloak-services",
"cpes": [
"cpe:/a:redhat:build_keycloak:"
]
},
{
"vendor": "Red Hat",
"product": "Red Hat Build of Keycloak",
"defaultStatus": "affected",
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"packageName": "rhbk/keycloak-rhel9",
"cpes": [
"cpe:/a:redhat:build_keycloak:"
]
},
{
"vendor": "Red Hat",
"product": "Red Hat Single Sign-On 7",
"defaultStatus": "unaffected",
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"packageName": "keycloak-services",
"cpes": [
"cpe:/a:redhat:red_hat_single_sign_on:7"
]
}
]
}
],
"metrics": {
"cvssMetricV31": [
{
"source": "[email protected]",
"type": "Primary",
"cvssData": {
"version": "3.1",
"vectorString": "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N",
"baseScore": 6.8,
"baseSeverity": "MEDIUM",
"attackVector": "NETWORK",
"attackComplexity": "HIGH",
"privilegesRequired": "LOW",
"userInteraction": "NONE",
"scope": "UNCHANGED",
"confidentialityImpact": "HIGH",
"integrityImpact": "HIGH",
"availabilityImpact": "NONE"
},
"exploitabilityScore": 1.6,
"impactScore": 5.2
}
]
},
"weaknesses": [
{
"source": "[email protected]",
"type": "Primary",
"description": [
{
"lang": "en",
"value": "CWE-20"
}
]
}
],
"references": [
{
"url": "https://access.redhat.com/security/cve/CVE-2026-97174",
"source": "[email protected]"
},
{
"url": "https://bugzilla.redhat.com/show_bug.cgi?id=2539961",
"source": "[email protected]"
}
]
}