PT-2026-52592 · Red Hat · Red Hat Build Of Keycloak+5

Published 2026-06-25 · Updated 2026-06-25 · CVE-2026-11800

Mitre

CVSS v3.1

8.1

High

Base vector

AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N

A flaw was found in Keycloak. This JWT algorithm confusion vulnerability in the JWT Authorization Grant flow allows an attacker with valid client credentials to bypass signature verification. By forging an assertion, the attacker can create unauthorized access tokens. This enables the attacker to impersonate any federated user linked to the affected Identity Provider, leading to unauthorized access and potential privilege escalation.

Fix

Improper Verification of Cryptographic Signature

Weakness Enumeration

CWE-347

Related Identifiers

CVE-2026-11800

Affected Products

Red Hat Build Of Keycloak

Red Hat Data Grid 8

Red Hat Jboss Enterprise Application Platform Expansion Pack

Red Hat Single Sign-On 7

Red Hat Build Of Keycloak 26.6

Red Hat Build Of Keycloak 26.6.4

References · 5

• https://access.redhat.com/errata/RHSA-2026:30084 · Vendor Advisory
• https://access.redhat.com/errata/RHSA-2026:30083 · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2026-11800 · Security Note
• https://bugzilla.redhat.com/show_bug.cgi?id=2487006 · Note
• https://access.redhat.com/security/cve/CVE-2026-11800 · Note