redhat build-keycloak CVE-2026-18217 vulnerability in Red Hat Products
Published on July 31, 2026

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 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.

NVD

Vulnerability Analysis

CVE-2026-18217 can be exploited with network access, requires user interaction. This vulnerability is consided to have a high level of attack complexity. The potential impact of an exploit of this vulnerability is considered to have no impact on confidentiality, with no impact on integrity, and no impact on availability.

Attack Vector:
NETWORK
Attack Complexity:
HIGH
Privileges Required:
NONE
User Interaction:
REQUIRED
Scope:
CHANGED
Confidentiality Impact:
NONE
Integrity Impact:
LOW
Availability Impact:
NONE

Timeline

Reported to Red Hat.

Made public.

Weakness Type

Improper Input Validation

The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.


Products Associated with CVE-2026-18217

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Affected Versions

Red Hat Build of Keycloak: Red Hat Build of Keycloak: Red Hat Build of Keycloak: Red Hat Data Grid 8: Red Hat JBoss Enterprise Application Platform Expansion Pack: Red Hat Single Sign-On 7: