Description
A flaw was found in the HOTP authentication mechanism of the keycloak-services component, which provides identity and access management services. The issue occurs because the system validates a one-time password and updates its internal counter in two separate steps without proper locking. An attacker with a users password could exploit this timing gap to use a single one-time code to log in multiple times simultaneously.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Red Hat | Red Hat Build of Keycloak | — | — |
| Red Hat | Red Hat Single Sign-On 7 | — | — |
Advisories 1
- WID-SEC-2026-4191 Keycloak: Mehrere Schwachstellen BSI CERT-Bund (WID) · Oct 29, 2026
References
- https://access.redhat.com/security/cve/CVE-2026-118030 vdb-entry
- RHBZ#2562005 issue-tracking