Description
A flaw was found in the Dynamic Client Registration flow of the Keycloak identity and access management server. The issue occurs because the registration process fails to filter security-sensitive client attributes when a new client is created. An attacker with a valid Initial Access Token can register a client that bypasses audience checks during token introspection. This allows the attacker to view sensitive identity information, roles, and session details from access tokens belonging to other applications in the same realm.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Red Hat | Red Hat Build of Keycloak | — | — |
| Red Hat | Red Hat Single Sign-On 7 | — | — |
Public exploits
Exploit or proof-of-concept code for this vulnerability is publicly available, which lowers the bar for attackers. Treat it as a reason to patch sooner.
GitHub 1 repository
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Dungsocool/CVE-2026-105306 ★ 0 · Oct 11, 2026
CVE-2026-105306: Token Introspection Audience Bypass via Dynamic Client Registration in Keycloak - Writeup by DungSoCool
Sources: PoC-in-GitHub, Metasploit Framework, Exploit-DB — updated daily. Only links are listed; no exploit code is hosted here.
Advisories 1
- WID-SEC-2026-3727 Keycloak: Mehrere Schwachstellen BSI CERT-Bund (WID) · Oct 4, 2026
References
- https://access.redhat.com/security/cve/CVE-2026-105306 vdb-entry
- RHBZ#2545802 issue-tracking