The CMS installer in Joomla! before 3.7.4 does not verify a user's ownership of a webspace, which allows remote authenticated users to gain control of the target application by leveraging Certificate Transparency logs.
The mailSend function in the isMail transport in PHPMailer before 5.2.18 might allow remote attackers to pass extra parameters to the mail command and consequently execute arbitrary code via a \" (backslash double quote) in a crafted Sender property.