CVE-2026-90997
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.
Statement
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.
Mitigation
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.
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 | NVD | cve.org | |
|---|---|---|---|
| Base Score | 7.4 | N/A | 7.4 |
| Attack Vector | Network | N/A | Network |
| Attack Complexity | High | N/A | High |
| Privileges Required | None | N/A | None |
| User Interaction | None | N/A | None |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | High | N/A | High |
| Integrity Impact | High | N/A | High |
| Availability Impact | None | N/A | None |
Vector
Red Hat: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
cve.org: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
Acknowledgements
Red Hat would like to thank Bruno Oliveira of IBM in collaboration with OpenAI for reporting this issue.
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