CVE-2026-63048 is a critical vulnerability in the Joomla Page Builder CK extension caused by unrestricted upload of files with dangerous types (CWE-434). Authenticated attackers can exploit this flaw to upload arbitrary files, potentially leading to remote code execution on the server hosting the Joomla site. The affected versions are from 1.0.0 up to and including 3.6.2. There is currently no vendor-provided patch or official remediation level. The vulnerability has a CVSS 4.0 base score of 9.4, reflecting its critical impact and ease of exploitation with low attack complexity and no user interaction required.

Successful exploitation allows an authenticated attacker to upload arbitrary files, including potentially malicious scripts, resulting in remote code execution. This can lead to full compromise of the affected Joomla site and underlying server. The vulnerability poses a critical risk to confidentiality, integrity, and availability of the system.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until an official fix is released, restrict access to the Page Builder CK extension to trusted users only and consider disabling file upload functionality if feasible. Monitor vendor channels for updates and apply patches promptly once available.