CVE-2026-56290

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

10.0 CriticalIn KEVPublic exploit

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.

Attack profile

How easy it is to exploit

Attack vector: Network
Complexity: Low
Privileges needed: None
User interaction: None

What an attacker can affect

Confidentiality: High
Integrity: High
Availability: High

Exploit likelihood

30.9%Up 30.6 points since Jun 30, 2026

What each source reports

CVE List Score used 10.0

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

Record: CVE-2026-56290
CVSS 4.0: 10.0 CriticalCVSS: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
Weakness: CWE-434
Updated: 2026-11-02

EUVDEUVD-2026-40121 10.0

Record: EUVD-2026-40121
CVSS 4.0: 10.0 CriticalCVSS: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
Updated: 2026-11-02

GitHub AdvisoriesGHSA-gxrr-wfg5-xqqf 10.0

The Joomla extension Page Builder CK is vulnerable to an unauthenticated arbitrary file upload...

The Joomla extension Page Builder CK is vulnerable to an unauthenticated arbitrary file upload that allows uploading executable files and leads to full RCE.

Record: GHSA-gxrr-wfg5-xqqf
CVSS 4.0: 10.0 CriticalCVSS: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/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:Y/R:X/V:X/RE:X/U:Red
CVSS 3.1: 9.8 CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Weakness: CWE-284, CWE-434
Updated: 2026-11-02

CISA KEV No score

Joomlack Page Builder Improper Access Control Vulnerability

Joomlack Page Builder contains an improper access control vulnerability that could allow for remote code execution via unauthenticated arbitrary file upload.

Record: CVE-2026-56290
Weakness: CWE-284
Updated: 2026-11-02

NVD 10.0

Record: CVE-2026-56290
CVSS 4.0: 10.0 CriticalCVSS: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/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:Y/R:X/V:X/RE:X/U:Red
CVSS 3.1: 9.8 CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Weakness: CWE-434
Updated: 2026-11-02

Affected products

Public exploits

Links only. Every CVE stores no exploit code.

Public exploits
Source	Link	Date
PoC in GitHub	sagsooz/PageBuilderCK-CVE-2026-56290-Exploit	2026-07-03
PoC in GitHub	shinthink/pbck-exploit	2026-07-04
Exploit-DB	Joomla Page Builder CK 3.5.10 - Arbitrary File Upload	2026-07-08
PoC in GitHub	Jenderal92/CVE-2026-56290	2026-07-08
PoC in GitHub	ChiefYoru/CVE-2026-56290_PoC	2026-07-19
PoC in GitHub	katranSefa/CVE-2026-56290	2026-09-05
Nuclei	Page Builder CK <= 3.5.10 - Unauthenticated Arbitrary File Upload

History

History
Recorded	Changed	Sources
Nov 3, 2026	exploitation, exploits
Nov 2, 2026	first indexed	CVE List, EUVD, Exploit-DB, GitHub Advisories, CISA KEV, Nuclei, NVD, PoC in GitHub

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2026-56290 is a critical vulnerability (CVSS 10.0) in Joomlack Page Builder, published June 29, 2026. CISA lists it as known to be exploited, since July 7, 2026. EUVD reports exploitation since July 7, 2026. Public exploit code exists. EPSS puts the chance of exploitation in the next 30 days at 30.9%, the 98th percentile. No source names a fixed version.