Description
A flaw was found in Keycloak. When deployed in stateless mode with MySQL or MariaDB, a mismatch in row-count semantics between the database driver and Keycloak's application logic allows an attacker to bypass replay protection. This vulnerability enables an attacker who intercepts single-use security artifacts, such as JWT client assertions, DPoP proofs, or one-time password (TOTP) codes, to replay them. Successful exploitation grants unauthorized access to the token endpoint or login flow.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Keycloak | Keycloak | 26.7.0 – < 26.7.4 | 26.7.4 |
| Red Hat | Red Hat Build of Keycloak | — | — |
Advisories 1
- WID-SEC-2026-3418 Keycloak: Mehrere Schwachstellen BSI CERT-Bund (WID) · Sep 17, 2026
References
- https://access.redhat.com/security/cve/CVE-2026-90997 vdb-entry
- RHBZ#2533141 issue-tracking