Actively exploited · Published Jun 29, 2026 · Assigned by Joomla
CVE-2026-56290Joomla Extension - joomlack.fr - Unauthenticated file upload in Page Builder CK extension < 3.6.0
Critical 10.0 Exploited
In plain English
A critical-severity unrestricted file upload in JoomlaCK.fr Page Builder CK extension for Joomla from joomlack.fr. Attackers are actively exploiting it in the wild (listed by CISA on July 7, 2026). The chance it is exploited in the next 30 days is estimated at 30.9% (higher than 98% of all known vulnerabilities). Ready-made attack tooling exists: Nuclei, public proof-of-concept code. 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.
CISA guidance
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.
Federal agencies must remediate by Jul 10, 2026.
Official description
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.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| joomlack.fr | JoomlaCK.fr Page Builder CK extension for Joomla | 1.0-3.6.0 |
Weakness: CWE-434 · 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
References
- https://www.joomlack.fr/ product
- https://mysites.guru/blog/pagebuilderck-unauthenticated-file-upload-rce/ third-party-advisory
- https://forum.joomlack.fr/index.php/page-builder-ck/21627-nouvelle-version-de-pbck-et-joomla-3 patch
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-56290 government-resource