Arbitrary file upload in Joomlack Page Builder Ck
CVE-2026-56290
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.
Vulnerability class: Unrestricted File Upload
EPSS: 0.833 (99.6th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.
Affected products
- Joomlack Page_builder_ck
- Joomlack.fr Page Builder Ck Extension For Joomla — versions 1.0-3.6.0
Weakness classification (CWE)
CISA KEV (Known Exploited Vulnerabilities)
This CVE is on the CISA KEV catalog, added on . CISA KEV inclusion means CISA has confirmed in-the-wild exploitation; US federal agencies are required to remediate within a published due date.
BOD 22-01 due date: .
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.
Public proof-of-concept exploits
References
- security@joomla.org (Product, product)
- 134c704f-9b21-4f2e-91b3-4a467353bcc0 (Patch, Issue Tracking)
- 134c704f-9b21-4f2e-91b3-4a467353bcc0 (Exploit, Third Party Advisory)
- 134c704f-9b21-4f2e-91b3-4a467353bcc0 (US Government Resource)
Frequently asked questions
- What is CVE-2026-56290?
- CVE-2026-56290 is a critical-severity vulnerability in Joomlack Page Builder Ck, classified under Unrestricted Upload of File with Dangerous Type. CVSS score: 9.8/10. Published 2026-06-29.
- How severe is CVE-2026-56290?
- Critical severity. CVSS v3 base score is 9.8 out of 10.
- Is CVE-2026-56290 known to be exploited?
- Yes. CVE-2026-56290 is listed in the CISA Known Exploited Vulnerabilities catalog (added 2026-07-07), indicating it is being actively exploited. 4 public proof-of-concept repositories are indexed.