Keycloak: keycloak: brute-force protection bypass in ciba flow

Description

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.

Timeline

Scores

EPSS (exploitation in 30 days)

0.38% · top 68% of all CVEs (11 Nov 2026)

CISA SSVC

Exploitation: none · Automatable: no · Technical impact: partial

The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 4.3.

Affected products

• Red Hat · Red Hat build of Keycloak 26.4

  • unaffected 26.4.14-1 – < *

• Red Hat · Red Hat build of Keycloak 26.4

  • unaffected 26.4-22 – < *

• Red Hat · Red Hat build of Keycloak 26.4

  • unaffected 26.4-22 – < *

• Red Hat · Red Hat build of Keycloak 26.4.14

  All versions: unaffected

• Red Hat · Red Hat build of Keycloak 26.6

  • unaffected 26.6.5-1 – < *

• Red Hat · Red Hat build of Keycloak 26.6

  • unaffected 26.6-11 – < *

• Red Hat · Red Hat build of Keycloak 26.6

  • unaffected 26.6-11 – < *

• Red Hat · Red Hat build of Keycloak 26.6.5

  All versions: unaffected

Affected packages

From reviewed advisories of the GitHub Advisory Database.

• Mavenorg.keycloak:keycloak-servicesGHSA-q6h7-xxp7-7429 (opens in a new tab)

What to do

Workaround: 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.

Sources

The same CVE in the primary databases and aggregators, to check against.

• CVE.org record (opens in a new tab)
• CVE List JSON (GitHub) (opens in a new tab)
• NVD (opens in a new tab)
• FIRST EPSS (opens in a new tab)
• EUVD EUVD-2026-32717 (opens in a new tab)
• OSV.dev (opens in a new tab)
• GitHub Advisory GHSA-q6h7-xxp7-7429 (opens in a new tab)
• CIRCL Vulnerability-Lookup (opens in a new tab)

Badge for a README or a ticket

[![CVE-2026-9798](https://cveledger.app/badge/CVE-2026-9798.svg)](https://cveledger.app/cve/CVE-2026-9798)

Record last updated 20 Aug 2026, 00:54 UTC.