---
id: CVE-2026-18208
title: >-
  A flaw was found in the OIDC token introspection endpoint of the
  keycloak-services component
summary: >-
  A flaw was found in the OIDC token introspection endpoint of the
  keycloak-services component. Keycloak is an open-source identity and access
  management solution used to secure modern applications and services. The issue
  occurs when a con…
severity: medium
cvss: 6.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N'
cwe:
  - CWE-862
vendor: redhat
product: build_of_keycloak
affected:
  - build_of_keycloak
published: '2026-07-31'
updated: '2026-08-07'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-18208'
references:
  - url: 'https://access.redhat.com/security/cve/CVE-2026-18208'
    label: secalert@redhat.com
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2508304'
    label: secalert@redhat.com
tags:
  - nvd
epss: 0.00341
epssPercentile: 0.24951
ingestedAt: '2026-08-08T14:22:57.398Z'
---

## Overview

A flaw was found in the OIDC token introspection endpoint of the keycloak-services component. Keycloak is an open-source identity and access management solution used to secure modern applications and services. The issue occurs when a confidential client, configured to receive signed JWT introspection responses, attempts to introspect a token issued for a different audience. Although the endpoint correctly identifies the token as inactive for that client, it still returns the full set of token claims within a signed JWT field. This allows an unauthorized client to bypass audience-based restrictions and access sensitive information contained in the token.

## Affected

- `build_of_keycloak`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.