What’s Vulnerable › Vulnerabilities

CVE-2026-18217: Keycloak-services: keycloak-services: saml http-redirect binding response preserves query string leading to parameter pollution

• Severity: medium (CVSS 4.7 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.3% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-07-31 · updated 2026-08-07
• Weakness: CWE-20

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.

Affected products

• Red Hat build of Keycloak 26.4: all versions

References

• https://access.redhat.com/security/cve/CVE-2026-18217
• https://bugzilla.redhat.com/show_bug.cgi?id=2508311

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