CVE-2026-56290KEV · OVERDUECWE-434unrestricted-file-upload

Joomlack Page Builder Improper Access Control Vulnerability

Critical · published June 29, 2026

Patch now

Confirmed exploited, and the score agrees

CVSS calls it critical at 9.8. It is confirmed in active exploitation. It sits in the 98.3th percentile for exploit probability.

106
days past CISA
deadline
CVSS v3.1
9.8
EPSS
31%
Percentile
98.3
In the wild
Confirmed
What it is

🚨 An unauthenticated file upload in Joomla's Page Builder CK extension could let attackers waltz in and wreak havoc—uploading whatever they like, including malicious executables! 🔥 Think of it like leaving the back door to your office wide open and letting anyone walk in with a suitcase full of sneaky surprises—total chaos could ensue if they decide to unpack! An attacker could exploit this vulnerability to upload malicious files, potentially gaining complete control over your server and all the sensitive data within—everything from user information to site configurations could be at risk! It’s absolutely devastating, as the full remote code execution (RCE) means they can execute any command they want, leaving your site in ruins.

Put simply

Think of it like leaving the back door to your office wide open and letting anyone walk in with a suitcase full of sneaky surprises—total chaos could ensue if they decide to unpack! This vulnerability in the Page Builder CK extension before version 3.6.0 permits unauthenticated users to upload arbitrary files, including executable ones, which can lead to full RCE if exploited.

What to do

An attacker could exploit this vulnerability to upload malicious files, potentially gaining complete control over your server and all the sensitive data within—everything from user information to site configurations could be at risk! It’s absolutely devastating, as the full remote code execution (RCE) means they can execute any command they want, leaving your site in ruins. To protect yourself, immediately update to Page Builder CK version 3.6.0 or later. Additionally, implement stricter file upload validations—only allow the necessary file types and confirm that uploads are sanitized. Regularly review your security policies to stay proactive. This is fixable! With the right steps, you'll be back in control in no time. 🛡️

The record
Technical detail
CVSS v3.1
9.8 · CRITICAL
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CVSS v4.0
Not supplied
EPSS
0.30866 · 98.3th percentile
Weakness
CWE-434 · Unrestricted Upload of File with Dangerous Type
Published
2026-06-29T19:16Z
KEV added
2026-07-07 · due 2026-07-10
Affected products (1)
ProductVersionsFixed in
joomlack/page_builder_ck< 3.6.03.6.0
References (4)
EPSS history
Timeline
  • 07 JUL 00:00Z
    Added to CISA KEV — remediate by Jul 10
    kev
  • 29 JUN 14:31Z
    Joomla Extension - joomlack.fr - Unauthenticated file upload in Page Builder CK extension < 3.6.0
    cvelistv5