CVE-2024-9666 — keycloak-quarkus-server
MEDIUMCVE-2024-9666 is a medium-severity (CVSS 4.7) CWE-444 vulnerability in org.keycloak:keycloak-quarkus-server. A fix is available for org.keycloak:keycloak-quarkus-server — see the affected versions and patch details below.
Org.keycloak/keycloak-quarkus-server: keycloak proxy header handling denial-of-service (dos) vulnerability
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-2024-9666.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
CVE-2024-9666 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 378,567 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
org.keycloak:keycloak-quarkus-server☕org.keycloak:keycloak-quarkus-serverReal-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
Keycloak versions 26 and earlier are vulnerable to a denial-of-service (DoS) attack through improper handling of proxy headers. When Keycloak is configured to accept incoming proxy headers, it may accept non-IP values, such as obfuscated identifiers, without proper validation. This can lead to costly DNS resolution operations, which an attacker could exploit to tie up IO threads and potentially cause a denial of service.
The attacker must have access to send requests to a Keycloak instance that is configured to accept proxy headers, specifically when reverse proxies do not overwrite incoming headers, and Keycloak is configured to trust these headers.
For Keycloak version 26, for successful exploitation includes: the realm must have SslRequired=EXTERNAL (the default), HTTP must be enabled, the instance must not be using a full hostname URL, access must come from behind a proxy (assuming the proxy overwrites the X-Forwarded-For header), and trusted proxies must not be set or must incorrectly trust the client from which the request is originating.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| ☕Maven | org.keycloak:keycloak-quarkus-server | all versions | No fix |
| ☕Maven | org.keycloak:keycloak-quarkus-server | ≥ 25.0.0&&< 26.0.6 | 26.0.6org.keycloak:keycloak-quarkus-server:26.0.6 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.keycloak:keycloak-quarkus-server, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
No patched version of org.keycloak:keycloak-quarkus-server has shipped for CVE-2024-9666 yet. Where your build allows, override or pin the dependency away from the vulnerable range, and apply any maintainer-recommended mitigation.
Workarounds
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.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2024-9666 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2024-9666. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
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.
Red Hat Enterprise Application Server 8 does not ship the affected component and so is not affected by this flaw.
| Product | Fixed in | Advisory |
|---|---|---|
| Red Hat build of Keycloak 24 | rhbk/keycloak-operator-bundle:24.0.9-1 | RHSA-2024:10175 |
| Red Hat build of Keycloak 24.0.9 | see advisory | RHSA-2024:10176 |
| Red Hat build of Keycloak 26.0 | rhbk/keycloak-operator-bundle:26.0.6-2 | RHSA-2024:10177 |
| Red Hat build of Keycloak 26.0.6 | see advisory | RHSA-2024:10178 |
Frequently Asked Questions
Is CVE-2024-9666 in your dependencies?
O3 Security finds CVE-2024-9666 across Maven dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.