CVE-2026-56290 remediation guide

Identify the affected asset

Confirm whether joomlack.fr JoomlaCK.fr Page Builder CK extension for Joomla, page builder ck is installed, record the deployed version and installation path, and identify exposed interfaces.

• Record the product name, package or appliance identifier, and installed version.
• Identify internet-facing, administrative, API, and internal access paths.
• Preserve the pre-change configuration and relevant service logs.

Validate the affected-version match

Compare the deployed version with the affected range: >= 1.0-3.6.0, < 3.6.0. Treat incomplete inventory results as unresolved.

Prioritize with independent signals

CISA has listed this vulnerability in the Known Exploited Vulnerabilities catalog. Combine this signal with asset criticality, exposure, compensating controls, and business impact.

Apply supported remediation

Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.

Verify the result

Confirm the resulting version, service health, authentication and access paths, monitoring coverage, and relevant security logs.

• Confirm the expected version and package state.
• Run a functional health check for critical service paths.
• Review authentication, error, application, and security monitoring logs.
• Reassess exposure if the supported fix cannot be applied.