CVE-2026-9798

Summary

A flaw was found in Keycloak, an open-source identity and access management solution. When a user account is temporarily locked due to repeated failed login attempts, an attacker with valid client credentials can exploit the Client-Initiated Backchannel Authentication (CIBA) flow to bypass this brute-force protection. This allows continued authentication attempts and token issuance even when the account should be locked, potentially enabling further unauthorized access attempts.

Affected Software

VendorProductVersion RangeStatus
Red HatRed Hat build of Keycloak 26.426.4.14-1 < *unaffected
Red HatRed Hat build of Keycloak 26.426.4-22 < *unaffected
Red HatRed Hat build of Keycloak 26.426.4-22 < *unaffected
Red HatRed Hat build of Keycloak 26.626.6.5-1 < *unaffected
Red HatRed Hat build of Keycloak 26.626.6-11 < *unaffected
Red HatRed Hat build of Keycloak 26.626.6-11 < *unaffected

Weaknesses

  • CWE-305: Authentication Bypass by Primary Weakness

Workarounds

To mitigate this issue, ensure that Client-Initiated Backchannel Authentication (CIBA) is not enabled in Keycloak realms unless explicitly required. If CIBA is enabled, consider disabling it to prevent the bypass of brute-force protection mechanisms. Consult Keycloak documentation for instructions on managing CIBA configuration.

ADP Enrichment

CISA ADP Vulnrichment

  • SSVC:
  • Exploitation: none
    • Automatable: no
    • Technical Impact: partial

References