CVE-2026-1035: Red Hat Build Of Keycloak 26.4

Low severity, CVSS 3.1. EPSS: 0.3% chance of exploitation in the next 30 days.

A flaw was found in the Keycloak server during refresh token processing, specifically in the TokenManager class responsible for enforcing refresh token reuse policies. When strict refresh token rotation is enabled, the validation and update of refresh token usage are not performed atomically. This allows concurrent refresh requests to bypass single-use enforcement and issue multiple access tokens from the same refresh token. As a result, Keycloak’s refresh token rotation hardening can be undermined.

Affected products

• Red Hat Red Hat Build Of Keycloak 26.4: before 26.4.11-1 (fixed in 26.4.11-1); before 26.4-14 (fixed in 26.4-14)
• Red Hat Red Hat Build Of Keycloak 26.4.11
• Red Hat Red Hat JBoss Enterprise Application Platform 8
• Red Hat Red Hat JBoss Enterprise Application Platform Expansion Pack
• Red Hat Red Hat Single Sign-On 7

Published 2026-01-21. Last modified 2026-06-17.