CVE-2026-4874 is a low-severity (CVSS 3.1) Server-Side Request Forgery (SSRF) vulnerability in org.keycloak:keycloak-services. A fix is available for org.keycloak:keycloak-services — see the affected versions and patch details below.
Keycloak Server-Side Request Forgery via OIDC token endpoint manipulation
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-2026-4874.
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-2026-4874 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 376,715 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-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 authenticated attacker can perform Server-Side Request Forgery (SSRF) by manipulating the client_session_host parameter during refresh token requests. This occurs when a Keycloak client is configured to use the backchannel.logout.url with the application.session.host placeholder. Successful exploitation allows the attacker to make HTTP requests from the Keycloak server’s network context, potentially probing internal networks or internal APIs, leading to information disclosure.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| ☕Maven | org.keycloak:keycloak-services | ≥ 26.5.0&&< 26.6.3 | 26.6.3org.keycloak:keycloak-services:26.6.3 |
| ☕Maven | org.keycloak:keycloak-services | all versions | 26.4.13org.keycloak:keycloak-services:26.4.13 |
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-services, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update org.keycloak:keycloak-services to 26.6.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-4874 is resolved across your whole dependency graph.
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-2026-4874 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2026-4874. 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.
This flaw allows an authenticated attacker to perform Server-Side Request Forgery (SSRF) by manipulating the `client_session_host` parameter during refresh token requests. This vulnerability is exploitable when a Keycloak client is configured to use the `backchannel.logout.url` with the `application.session.host`…
| Product | Fixed in | Advisory |
|---|---|---|
| Red Hat build of Keycloak 26.4 | rhbk/keycloak-operator-bundle:26.4.13-1 | RHSA-2026:30050 |
| Red Hat build of Keycloak 26.4.13 | rhbk/keycloak-rhel9 | RHSA-2026:30049 |
| Red Hat build of Keycloak 26.6 | rhbk/keycloak-operator-bundle:26.6.3-3 | RHSA-2026:25097 |
| Red Hat build of Keycloak 26.6.3 | rhbk/keycloak-rhel9 | RHSA-2026:25098 |
Frequently Asked Questions
Is CVE-2026-4874 in your dependencies?
O3 Security finds CVE-2026-4874 across Maven dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.