Log in Start free

Vulnerability · Published May 28, 2026 · Assigned by redhat

CVE-2026-9798Keycloak: keycloak: brute-force protection bypass in ciba flow

Medium 4.3

In plain English

A medium-severity security flaw in Red Hat build of Keycloak 26.4 from Red Hat. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 32% of all known vulnerabilities).

Severity (CVSS 3.1)4.3Medium
Exploit odds (30 days)0.4%top 68.3% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official 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.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Mavenorg.keycloak:keycloak-servicesno fix listedGHSA-q6h7-xxp7-7429
Mavenorg.keycloak:keycloak-servicesno fix listedGHSA-q6h7-xxp7-7429

Affected products (as reported)

VendorProductVersions
Red Hat Red Hat build of Keycloak 26.4 see references
Red Hat Red Hat build of Keycloak 26.4 see references
Red Hat Red Hat build of Keycloak 26.4 see references
Red Hat Red Hat build of Keycloak 26.4.14 see references
Red Hat Red Hat build of Keycloak 26.6 see references
Red Hat Red Hat build of Keycloak 26.6 see references
Red Hat Red Hat build of Keycloak 26.6 see references
Red Hat Red Hat build of Keycloak 26.6.5 see references

Weakness: CWE-305 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N

References