diff -ruN squirrelmail-webmail-1.4.22/class/deliver/Deliver_SendMail.class.php squirrelmail-webmail-1.4.22-fix-CVE-2017-7692/class/deliver/Deliver_SendMail.class.php
--- squirrelmail-webmail-1.4.22/class/deliver/Deliver_SendMail.class.php  2011-01-06 02:44:03.000000000 +0000
+++ squirrelmail-webmail-1.4.22-fix-CVE-2017-7692/class/deliver/Deliver_SendMail.class.php  2017-04-18 11:42:26.505181944 +0000
@@ -93,9 +93,9 @@
         $envelopefrom = trim($from->mailbox.'@'.$from->host);
         $envelopefrom = str_replace(array("\0","\n"),array('',''),$envelopefrom);
         // save executed command for future reference
-        $this->sendmail_command = "$sendmail_path $this->sendmail_args -f$envelopefrom";
+        $this->sendmail_command = escapeshellcmd("$sendmail_path $this->sendmail_args -f") . escapeshellarg($envelopefrom);
         // open process handle for writing
-        $stream = popen(escapeshellcmd($this->sendmail_command), "w");
+        $stream = popen($this->sendmail_command, "w");
         return $stream;
     }