CVE-2026-18217 — Keycloak-services: keycloak-services: saml http-redirect binding response preserves query string leading to parameter pollution
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 authenticat…
Published: 2026-07-31 · CVSS: 3.4 · CVSS 3.1
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.
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7