--- exim.pl.16.old	2017-11-05 00:05:29.000000000 -0500
+++ exim.pl.16	2017-11-05 00:14:33.000000000 -0500
@@ -22,6 +22,33 @@
 	return -1;
 }
 
+sub safe_name
+{
+	my ($name) =  @_;
+
+	if ($name =~ /\//)
+	{
+		return 0;
+	}
+
+	if ($name =~ /\\/)
+	{
+		return 0;
+	}
+	
+	if ($name =~ /\|/)
+	{
+		return 0;
+	}
+
+	if ($name =~ /\.\./)
+	{
+		return 0;
+	}
+
+	return 1;
+}
+
 # hit_limit_user
 # checks to see if a username has hit the send limit.
 # returns:
@@ -37,6 +64,11 @@
 	my $count = 0;
 	my $email_limit = 0;
 
+	if (!safe_name($username))
+	{
+		return 2;
+	}
+
 	if (open (LIMIT, "/etc/virtual/limit_$username"))
 	{
 		$email_limit = int(<LIMIT>);
@@ -78,6 +110,11 @@
 {
 	my($user,$domain) = @_;
 
+	if (!safe_name($user) || !safe_name($domain))
+	{
+		return 2;
+	}
+
 	my $user_email_limit = 0;
 	if (open (LIMIT, "/etc/virtual/$domain/limit/$user"))
 	{
@@ -136,11 +173,11 @@
 		}
 	}
 
-        if ($username =~ /\|/)
-        {
-                Exim::log_write("SMTPAuth: Invalid username: $username");
-                return "no";
-        }
+	if (!safe_name($username))
+	{
+		Exim::log_write("SMTPAuth: Invalid username: $username");
+		return "no";
+	}
 
 	if ($username =~ /\@/)
 	{
@@ -254,6 +291,12 @@
 	my $username = $auth_id;
 	my @pw;
 
+	if (!safe_name($username))
+	{
+		Exim::log_write("find_uid_auth_id: Invalid username: $username");
+		return "-1";
+	}
+
 	if ($auth_id =~ /\@/)
 	{
 		$unixuser = 0;
@@ -461,6 +504,12 @@
 		my $domain="";
 		($user, $domain) = (split(/@/, $authenticated_id));
 
+		if (!safe_name($authenticated_id))
+		{
+			Exim::log_write("check_limits: Invalid username: $authenticated_id");
+			return "no";
+		}
+
 		if ($domain ne "")
 		{
 			my $user_email_limit = 0;
@@ -544,6 +593,12 @@
 	my $pss = "";
 	my $entry = "";
 
+	if (!safe_name($dmn) || !safe_name($lp))
+	{
+		Exim::log_write("save_virtual_user: Invalid username: $lp or domain: $dmn");
+		return "no";
+	}
+
 	open (PASSWD, "/etc/virtual/$dmn/passwd") || return "no";
 
 	while ($entry = <PASSWD>) {