The vulnerability in LibreBooking involves improper handling of the template name during the save action in the email template editor. Because the submitted template name is used directly in the destination file path without proper validation or sanitization, an attacker with administrator privileges can perform path traversal to write files outside the designated template directory. This can lead to arbitrary code execution on the affected system. The vulnerability is tracked as CVE-2026-61343 and classified under CWE-23 (Relative Path Traversal).

An attacker with administrator credentials can exploit this vulnerability to write arbitrary files outside the intended directory, potentially leading to remote code execution. This compromises the integrity and security of the affected system by allowing unauthorized code execution.

A fix for this vulnerability is available in LibreBooking version 5.1.0. Users should upgrade to version 5.1.0 or later to remediate this issue. No additional mitigation steps are indicated.