CVE-2026-56290 CRITICAL

CVE-2026-56290: Joomla Extension - joomlack.fr - Unauthenticated file upload in Page Builder CK extension < 3.6.0

Vendor Joomlack.fr
Product JoomlaCK.fr Page Builder CK extension for Joomla
Weakness CWE-434 · Unrestricted file upload
KEV Status Known Exploited
Published June 29, 2026
Last update July 23, 2026

CVSS base score

10.0/10
Attack vector Network
Attack complexity Low
Privileges required None
User interaction None
Confidentiality
Integrity

CVSS vector

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:A/AU:Y/U:Red

What the vulnerability does

01Description

Joomla Extension - joomlack.fr - Unauthenticated file upload in Page Builder CK extension < 3.6.0 - The Joomla extension Page Builder CK is vulnerable to an unauthenticated arbitrary file upload that allows uploading executable files and leads to full RCE.

Explanation of Vulnerability in Simple Terms

02Summary

The JoomlaCK.fr Page Builder CK extension for Joomla contains an access control flaw that allows unauthenticated attackers to perform unauthorized actions over the network. The vulnerability affects versions 1.0-3.6.0 and earlier. No patch information is currently available. Site administrators should monitor for updates from the vendor.

What an attacker can do

03Attacker Capabilities

Perform unauthorized actions on the Joomla site without authentication.

Potential impact on your site

04Site Impact

Attackers can modify or access sensitive site data and functionality without logging in.

Conditions required to exploit

05Prerequisites

Network access only; no authentication or user interaction required.

CISA mandated remediation

06CISA Required Action

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.

Key dates

07Disclosure timeline

June 29, 2026 CVE published
July 23, 2026 Record updated

External resources

08References

Related vulnerabilities

09Related CVE