Cve 2026 90997

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.

This vulnerability in Keycloak, when deployed in stateless mode with MySQL or MariaDB, is of High impact. It allows an attacker to bypass replay protection for single-use security artifacts, such as JWT client assertions and TOTP codes, leading to unauthorized access. Exploitation requires an attacker to intercept these short-lived artifacts, which typically necessitates a Man-in-the-Middle position or application-level compromise. This affects community only, it does not affect Red Hat build of Keycloak.

To mitigate this issue, configure the JDBC connection string for MySQL/MariaDB to explicitly set `useAffectedRows=true`. This ensures the database driver correctly reports affected rows, preventing the replay protection bypass. This mitigation is applicable only when Keycloak is deployed in stateless mode and utilizes MySQL or MariaDB as its database. A restart of the Keycloak service will be required for the configuration change to take effect.

Bugzilla 2533141 : keycloak-services: Keycloak: Replay protection bypass leads to unauthorized access via database driver semantics mismatch

CWE-294 : Authentication Bypass by Capture-replay

Common Vulnerability Scoring System (CVSS) Score Details

Info alert: Important note

CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications ).

The following CVSS metrics and score provided are preliminary and subject to review.

CVSS v3 Score Breakdown

Red Hat: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

Understanding the Weakness (CWE)

Technical Impact: Gain Privileges or Assume Identity

Messages sent with a capture-relay attack allow access to resources which are not otherwise accessible without proper authentication.

Frequently Asked Questions

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Upgrade to a supported product version that includes a fix for this vulnerability (recommended).

Apply a mitigation (if one exists).

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Apply a mitigation (if one exists).

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