A flaw was found in the token sanitization logic of Keycloak, an open source identity and access management solution. The issue occurs when a protocol mapper is configured to emit structured claims using the JSON type. The security check designed to remove unauthorized role mappings only looks for standard Java maps and fails to recognize Jackson based JSON objects. This allows an attacker to inject forged client roles into security tokens, which could lead to unauthorized access to protected resources.
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Fixes

Solution

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Workaround

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History

Fri, 06 Nov 2026 00:15:00 +0000

Type Values Removed Values Added
Description A flaw was found in the token sanitization logic of Keycloak, an open source identity and access management solution. The issue occurs when a protocol mapper is configured to emit structured claims using the JSON type. The security check designed to remove unauthorized role mappings only looks for standard Java maps and fails to recognize Jackson based JSON objects. This allows an attacker to inject forged client roles into security tokens, which could lead to unauthorized access to protected resources.
Title keycloak-services: keycloak-services: Protocol mapper with jsonType=JSON bypasses token sanitization
Weaknesses CWE-20
References
Metrics threat_severity

None

cvssV3_1

{'score': 6.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N'}

threat_severity

Moderate


Projects

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cve-icon MITRE

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cve-icon Vulnrichment

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cve-icon NVD

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cve-icon Redhat

Severity : Moderate

Publid Date: 2026-11-05T00:00:00Z

Links: CVE-2026-97848 - Bugzilla

cve-icon OpenCVE Enrichment

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Weaknesses