CVE-2025-65319 affects Blue Mail versions up to and including 1.140.103. When users interact with attachments, the application saves documents to the file system without applying the Mark-of-the-Web (MOTW) tag. MOTW is a security feature used by Windows and other software to identify files downloaded from untrusted sources and apply appropriate protections. The absence of this tag can allow attackers to circumvent these protections, potentially leading to unauthorized access or execution of malicious content. The vulnerability is classified under CWE-693 and has a CVSS 3.1 base score of 9.1, reflecting its critical nature with network attack vector, low complexity, no privileges or user interaction required, and high confidentiality and integrity impacts.

The vulnerability allows attackers to bypass built-in file protection mechanisms of Windows OS and third-party software by saving files without the Mark-of-the-Web tag. This can lead to unauthorized access or execution of malicious files that would otherwise be flagged or restricted, compromising confidentiality and integrity of the system. Availability is not impacted. There are no known exploits in the wild at this time.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Since no patch or official fix information is provided, users of Blue Mail should monitor vendor communications for updates. Until a fix is available, cautious handling of attachments and limiting exposure to untrusted files is advised.