Skip to content
4.2 Medium

CVE-2026-118030 Keycloak-services: keycloak-services: hotp race condition allows single otp code reuse across concurrent logins

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.

CVSS 3.1 detail

Vector CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:N

Exploitable remotely over the network, with an ordinary account and without any user action; the impact on data or service is limited.

Attack vector
Network
Attack complexity
High
Privileges required
Low
Interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
Low
Availability
None

Affected products and versions

Product Affected versions Fixed in
Red Hat Build of Keycloak Versions not published
Red Hat Single Sign-On 7 Versions not published
The 277 CVEs of Red Hat Build of Keycloak →
Track this CVE