The vulnerability CVE-2026-28027 in ThemeREX Kayon (versions up to 1.3) is caused by improper validation of filenames used in PHP include or require statements, resulting in a Local File Inclusion (LFI) vulnerability. This flaw allows remote attackers to include files from the local filesystem, potentially leading to disclosure of sensitive information, code execution, or denial of service. The CVSS 3.1 base score is 8.1 with vector AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H, indicating network attack vector, high attack complexity, no privileges or user interaction required, and high impact on confidentiality, integrity, and availability. No patch or vendor advisory is currently available to confirm remediation status.

Successful exploitation of this vulnerability can lead to full compromise of the affected system's confidentiality, integrity, and availability by allowing an attacker to include and execute local files. This can result in unauthorized access to sensitive data, code execution, or service disruption. However, the attack complexity is high, which may limit exploitation scenarios. No known exploits in the wild have been reported at this time.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until an official fix is available, users should restrict access to vulnerable endpoints, apply strict input validation on filenames used in include/require statements, and consider disabling or limiting PHP functions that allow file inclusion if feasible. Monitor ThemeREX vendor communications for updates and patches.