CVE-2026-56290
CriticalExploitedPublic exploitThe Joomla extension Page Builder CK is vulnerable to an unauthenticated arbitrary file upload that allows uploading executable files and leads to full RCE.
Published Jun 29, 2026 · Updated Oct 8, 2026
Key Facts
Patch immediately- CVE-2026-56290 is a critical-severity vulnerability (CVSS 10.0 v4) affecting Page Builder Ck (Joomlack), JoomlaCK.fr Page Builder CK extension for Joomla.
- It is exploited in the wild, listed in CISA KEV, Industry KEV feed, CIRCL KEV, ENISA EUVD since Jun 27, 2026. Public exploit code is available.
- EPSS estimates a 31% probability of exploitation in the next 30 days.
- Fixed versions are available, including Page Builder Ck 3.6.0.
- Brandefense priority: patch immediately, because it is listed as exploited in the wild.
CVSS v4
10.0
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
EPSS (30-day exploit likelihood)
31%
Higher than 98.2% of all scored CVEs
Exploited in the wild
Yes
4 catalog listings
Public exploit code
Available
Proof-of-concept or weaponized module
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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.
Known-Exploited Catalog Listings
| Catalog | Added | Remediation due | Ransomware use |
|---|---|---|---|
| CISA KEV | Jul 7, 2026 | Jul 10, 2026 | Not reported |
| Industry KEV feed | Jun 27, 2026 | Jul 10, 2026 | Not reported |
| CIRCL KEV | Jul 7, 2026 | Jul 10, 2026 | Not reported |
| ENISA EUVD | Jul 7, 2026 | n/a | Not reported |
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.
Affected Products
2 affected entries in total| Product | Affected versions | Fixed in |
|---|---|---|
| Page Builder CkJoomlack | See advisory | 3.6.0 |
| JoomlaCK.fr Page Builder CK extension for Joomla | >= 1.0-3.6.0 | n/a |
Patched Releases
Page Builder Ck
3.6.0
Timeline
Added to Industry KEV feed
Jun 27, 2026
Publicly disclosed
Jun 29, 2026
Added to CISA KEV
Jul 7, 2026
Added to CIRCL KEV
Jul 7, 2026
Added to ENISA EUVD
Jul 7, 2026
Last updated
Oct 8, 2026
Weakness Type
- CWE-284 Improper Access Control
- CWE-434 Unrestricted Upload of File with Dangerous Type
References
- exploitVulnCheck exploitation report
- exploitVulnCheck exploitation report
- exploitVulnCheck exploitation report
- exploitExploitDB-52626
- exploitVulnCheck exploitation report
FAQ
Common Questions.
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: Page Builder Ck (Joomlack); JoomlaCK.fr Page Builder CK extension for Joomla versions >= 1.0-3.6.0. The full list is in the CVE brief.
It is exploited in the wild, listed in CISA KEV, Industry KEV feed, CIRCL KEV, ENISA EUVD since Jun 27, 2026.
Yes. It was added on Jul 7, 2026 with a federal remediation due date of Jul 10, 2026.
Public exploit code is available.
Fixed versions are available, including Page Builder Ck 3.6.0.
Brandefense priority: patch immediately, because it is listed as exploited in the wild.
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