CVE-2025-71326 is an unquoted search path vulnerability affecting AVAST Antivirus 25.11, specifically in the SecureLine service. The unquoted service path allows local attackers with limited privileges to place malicious executables in locations that the service path resolves to, resulting in code execution with elevated SYSTEM privileges. This vulnerability is classified as high severity with a CVSS 4.0 score of 8.5. There is no vendor advisory or patch currently available, and the product is not a cloud service, so remediation depends on vendor updates or manual mitigation.

Successful exploitation enables local non-privileged users to execute arbitrary code with SYSTEM privileges, potentially leading to full system compromise. This elevates the attacker's permissions beyond their initial access level, posing a significant security risk on affected systems.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until an official fix is released, users should restrict local access to trusted users only and monitor for suspicious activity related to the SecureLine service. Avoid placing executables or scripts in directories referenced by the service path. Follow up with Avast for updates or official patches.