HestiaCP before 1.9.5 contains an authenticated OS command injection vulnerability that allows low-privilege authenticated users to execute arbitrary commands as root by injecting a single-quote character into unvalidated DNS record types. Attackers can exploit insufficient input validation in is_dns_record_format_valid() combined with unsafe eval-based parsing in update_domain_zone() to prematurely close a variable assignment string and achieve full root code execution on the underlying host in a single DNS record creation step.