CVE-2026-9689CWE-1288

CVE-2026-9689

Medium · published May 27, 2026

CVSS v3.1
4.2
EPSS
0%
Percentile
36.2
In the wild
Unconfirmed
What it is

A flaw was found in Keycloak, an open-source identity and access management solution. When a client application is configured to accept broad redirect Uniform Resource Identifiers (URIs), a remote attacker can manipulate the authentication process by crafting a special web address. If a user clicks this link, the client application might incorrectly prioritize attacker-controlled information over legitimate data. This vulnerability, known as HTTP parameter pollution, could allow an attacker to bypass security measures or gain unauthorized access to resources.

The record
Technical detail
CVSS v3.1
4.2 · MEDIUM
Vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:N
CVSS v4.0
Not supplied
EPSS
0.00430 · 36.2th percentile
Weakness
CWE-1288 · Improper Validation of Consistency within Input
Published
2026-05-27T16:17Z
Affected products (1)
ProductVersionsFixed in
redhat/build_of_keycloakall versions—
References (6)
EPSS history
Timeline
  • 27 MAY 10:35Z
    Keycloak: org.keycloak.protocol.oidc: http parameter pollution in oidc redirect uri allows response parameter duplication - #ghi-604
    cvelistv5