CVE-2026-18217
Keycloak-services: keycloak-services: saml http-redirect binding response preserves query string leading to parameter pollution
Description
A flaw was found in the SAML protocol implementation of Keycloak, an open-source identity and access management solution. The issue occurs when Keycloak handles SAML authentication requests using the HTTP-Redirect binding. If a client is configured with a wildcard redirect URL, an attacker can craft a request that includes malicious parameters. When a user authenticates, Keycloak appends its legitimate response to the attacker's parameters. This can cause some service providers to process the attacker's data instead of the real login information, potentially leading to a user being logged into the wrong account.
CVSS Vector Breakdown
AV:NAttack VectorAC:HAttack ComplexityPR:NPrivileges RequiredUI:RUser InteractionS:CScopeC:NConfidentialityI:LIntegrityA:NAvailabilityWeaknesses
Affected Products
Exploitability
Attack Graph
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MITRE ATT&CK
1 techniqueReferences
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