MAILsweeper for SMTP 4.3.6 and 4.3.7 allows remote attackers to cause a denial of service (CPU consumption) via a PowerPoint attachment that either (1) is corrupt or (2) contains "embedded objects."

Clearswift MAILsweeper 4.0 through 4.3.7 allows remote attackers to bypass filtering via a file attachment that contains "multiple extensions combined with large blocks of white space."

Clearswift MAILsweeper for SMTP 4.3.6 SP1 does not execute custom "on strip unsuccessful" hooks, which allows remote attackers to bypass e-mail attachment filtering policies via an attachment that MAILsweeper can detect but not remove.

MAILsweeper for SMTP 4.3 allows remote attackers to bypass virus protection via a mail message with a malformed zip attachment, as exploited by certain MIMAIL virus variants.

Clearswift MAILsweeper 4.x allows remote attackers to bypass attachment detection via an attachment that does not specify a MIME-Version header field, which is processed by some mail clients.

The File Blocker feature in Clearswift MAILsweeper for SMTP 4.2 allows remote attackers to bypass e-mail attachment filtering policies via a modified name in a Content-Type header.

MAILsweeper for SMTP 3.x does not properly handle corrupt CDA documents in a ZIP file and hangs, which allows remote attackers to cause a denial of service.