Cyber Threat Intelligence
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CRITICAL · CVSS 9.8 CISA Known Exploited Vulnerability

CVE-2026-56290

Joomlack Page Builder Improper Access Control Vulnerability

Joomlack Page Builder

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.

CVSS
9.8
CRITICAL
EPSS
83.3%
30-day exploitation
Ransomware groups
0
recorded exploiting
Published
29 Jun 2026
CWE-434

Exploitation status

CISA Known Exploited Vulnerabilities

Listed by CISA on 7 July 2026. US federal agencies were required to remediate it by 10 July 2026.

EPSS — exploitation probability

FIRST puts the probability of exploitation activity in the next 30 days at 83.3%, which is higher than 99.7% of all scored vulnerabilities. EPSS is a forecast of activity, not a measure of severity, and it is rescored daily.

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Frequently asked questions

Is CVE-2026-56290 being exploited by ransomware groups?

No ransomware group in this database is currently recorded as exploiting CVE-2026-56290.

What does CVE-2026-56290 affect?

CVE-2026-56290 affects Joomlack Page Builder. 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.

How severe is CVE-2026-56290?

CVE-2026-56290 is rated CRITICAL with a CVSS base score of 9.8. EPSS puts the probability of exploitation in the next 30 days at 83.3%, higher than 99.7% of all scored vulnerabilities. It is listed in the CISA Known Exploited Vulnerabilities catalog, with a federal remediation deadline of 10 July 2026.

How should organisations respond to CVE-2026-56290?

Apply the vendor patch for Joomlack Page Builder as the first priority, and treat any internet-facing instance as the most urgent. Because this vulnerability is associated with ransomware activity, also review whether the affected systems were reachable before patching, rather than assuming that patching alone closes the incident.