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OpenAdvisories
High · 7.4 CVE-2026-90997 EUVD-2026-82396

Keycloak-services: keycloak: replay protection bypass leads to unauthorized access via database driver semantics mismatch

Published Sep 17, 2026 · Updated Sep 25, 2026 · Assigned by redhat

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

VendorProductAffectedFixed
Keycloak Keycloak 26.7.0 – < 26.7.4 26.7.4
Red Hat Red Hat Build of Keycloak — —

Advisories 1

References