CVE-2026-9798 is a medium-severity (CVSS 4.3) CWE-305 vulnerability in org.keycloak:keycloak-services. No vendor fix is recorded yet; mitigation options are listed below.
Keycloak has an Authentication Bypass by Primary Weakness
Exploitation Status
No confirmed exploitation observed yet
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-9798.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
CVE-2026-9798 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.
Where this sits among everything scored
Of 385,386 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.
Real-World Exposure
org.keycloak:keycloak-services☕org.keycloak:keycloak-servicesReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Maven packages — download data is not available via public APIs for these ecosystems.
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
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| ☕Maven | org.keycloak:keycloak-services | all versions | No fix |
| ☕Maven | org.keycloak:keycloak-services | ≥ 26.5.0 | No fix |
Affected Products
build of keycloakredhatDetection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.keycloak:keycloak-services, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Remediation status
No patched version of org.keycloak:keycloak-services has shipped for CVE-2026-9798 yet. Where your build allows, override or pin the dependency away from the vulnerable range, and apply any maintainer-recommended mitigation.
Mitigate without a patch
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
This flaw in Keycloak's Client-Initiated Backchannel Authentication (CIBA) flow is rated as Low impact. The vulnerability allows bypassing brute-force protection when a user account is locked, but only if CIBA is explicitly enabled and configured (non-default), and the user approves the authentication request on their…
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.Source: Red Hat security advisory for CVE-2026-9798 (CC BY 4.0)
| Product | Fixed in | Advisory |
|---|---|---|
| Red Hat build of Keycloak 26.4 | rhbk/keycloak-operator-bundle:26.4.14-1 | RHSA-2026:50847 |
| Red Hat build of Keycloak 26.4.14 | rhbk/keycloak-rhel9 | RHSA-2026:50846 |
| Red Hat build of Keycloak 26.6 | rhbk/keycloak-operator-bundle:26.6.5-1 | RHSA-2026:50849 |
| Red Hat build of Keycloak 26.6.5 | see advisory | RHSA-2026:50848 |
Frequently Asked Questions
Is CVE-2026-9798 in your dependencies?
Find it across Maven, including transitive dependencies.