CVE-2026-18208 Details
Description
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.
An information disclosure vulnerability exists in the OIDC token introspection endpoint of Keycloak's keycloak-services component. This flaw allows a confidential client to access sensitive token claims intended to be restricted by audience-based access controls. The issue arises when a client introspects a token issued for a different audience. Although the endpoint correctly marks the token as inactive for that client, it still leaks the full set of token claims in a signed JWT field. This vulnerability enables unauthorized clients to bypass audience restrictions and access internal identity information, such as roles, groups, and user attributes, they are not authorized to view.
Metrics
CVSS 4.0 Severity and Vector Strings:
No CVSS 4.0 data is available for this CVE.
CVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
CISA-ADP
Assessed Jul 31, 2026References to Advisories, Solutions, and Tools
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| URL | Source(s) | Tag(s) |
|---|---|---|
| https://access.redhat.com/security/cve/CVE-2026-18208 | [email protected] | Vendor Advisory |
| https://bugzilla.redhat.com/show_bug.cgi?id=2508304 | [email protected] | Issue TrackingVendor Advisory |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-862 | Missing Authorization | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| redhat build of keycloak | All versions |
CPE
Remediation
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Change History
3 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Aug 7, 2026 | Initial Analysis | [email protected] |
| Jul 31, 2026 | CVE Modified | CISA-ADP |
| Jul 31, 2026 | New CVE Received | [email protected] |