CVE-2026-18209
3.4 · LOWOverview
CVE-2026-18209 is a low-severity vulnerability affecting redhat build_of_keycloak. It was published on July 31, 2026 and has a CVSS 3.1 base score of 3.4 (LOW).
This vulnerability has a CVSS 3.1 base score of 3.4, rated LOW. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.
Technical Description
A flaw was found in the keycloak-services component of Keycloak, which handles OpenID Connect (OIDC) authentication flows. The issue occurs because the security check designed to prevent HTTP parameter pollution only inspects the query portion of a redirect URL and ignores the fragment portion. When a client is configured with a wildcard redirect URI, an attacker can use this to inject duplicate security parameters into the login response. If a client application is not configured correctly, it might trust the attacker's injected data instead of the real security information from Keycloak, leading to session fixation or account confusion.
Remediation
Check the references section for vendor advisories and patches from redhat. Update build_of_keycloak to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
Affected Products
| Vendor | Product | Versions | Status |
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Frequently Asked Questions
What is CVE-2026-18209?
CVE-2026-18209 is a low-severity vulnerability affecting redhat build_of_keycloak. It was published on July 31, 2026 and has a CVSS 3.1 base score of 3.4 (LOW).
How severe is CVE-2026-18209?
This vulnerability has a CVSS 3.1 base score of 3.4, rated LOW. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.
How do I fix or remediate CVE-2026-18209?
Check the references section for vendor advisories and patches from redhat. Update build_of_keycloak to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
How can CyberStrike help with CVE-2026-18209?
CyberStrike's AI-powered security agents can automatically detect CVE-2026-18209 across your infrastructure using autonomous pentesting, DAST scanning, and HackBrowser. The platform continuously monitors for known vulnerabilities and provides actionable remediation guidance prioritized by real-world exploitability.
How CyberStrike Helps
AI agents map your attack surface to find vulnerabilities like this one.
Automated penetration testing that runs continuously, not just quarterly.
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Browser-based exploitation validates findings with real proof-of-concept.
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