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Vulnerability · Published Jul 31, 2026 · Assigned by redhat

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

Low 3.4

In plain English

A low-severity improper input validation in Red Hat Build of Keycloak from Red Hat. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 30% of all known vulnerabilities).

Severity (CVSS 3.1)3.4Low
Exploit odds (30 days)0.4%top 69.6% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official 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 (as reported)

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

Weakness: CWE-20 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:N/I:L/A:N

References