diff --git a/fetchmail/check.cgi b/fetchmail/check.cgi
index 5a324c637..d00627b8e 100755
--- a/fetchmail/check.cgi
+++ b/fetchmail/check.cgi
@@ -17,14 +17,14 @@ else {
 
 &ui_print_unbuffered_header($uheader, $text{'check_title'}, "");
 
-$cmd = "$config{'fetchmail_path'} -v -f '$file'";
+$cmd = "$config{'fetchmail_path'} -v -f ".quotemeta($file);
 if ($config{'mda_command'}) {
-	$cmd .= " -m '$config{'mda_command'}'";
+	$cmd .= " -m ".quotemeta($config{'mda_command'});
 	}
 if (defined($in{'idx'})) {
 	@conf = &parse_config_file($file);
 	$poll = $conf[$in{'idx'}];
-	$cmd .= " $poll->{'poll'}";
+	$cmd .= " ".quotemeta($poll->{'poll'});
 	}
 
 print &text('check_exec', "<tt>$cmd</tt>"),"<p>\n";
diff --git a/fetchmail/edit_cron.cgi b/fetchmail/edit_cron.cgi
index 5491d06d1..57599d4a3 100755
--- a/fetchmail/edit_cron.cgi
+++ b/fetchmail/edit_cron.cgi
@@ -19,10 +19,10 @@ print &ui_table_start($text{'cron_header'}, "width=100%", 2);
 
 if ($job) {
 	if ($job->{'command'} =~ /--mail\s+(\S+)/) {
-		$mail = `echo $1`;
+		($mail = $1) =~ s/\\(.)/$1/g;
 		}
 	elsif ($job->{'command'} =~ /--file\s+(\S+)/) {
-		$file = `echo $1`;
+		($file = $1) =~ s/\\(.)/$1/g;
 		}
 	elsif ($job->{'command'} =~ /--output/) {
 		$output = 1;
@@ -31,7 +31,7 @@ if ($job) {
 		$owner = 1;
 		}
 	if ($job->{'command'} =~ /--user\s+(\S+)/) {
-		$user = $1;
+		($user = $1) =~ s/\\(.)/$1/g;
 		}
 	if ($job->{'command'} =~ /--errors/) {
 		$errors = 1;
diff --git a/fetchmail/save_cron.cgi b/fetchmail/save_cron.cgi
index 0de6d35f1..4040fd6da 100755
--- a/fetchmail/save_cron.cgi
+++ b/fetchmail/save_cron.cgi
@@ -36,7 +36,7 @@ if ($in{'errors'}) {
 	}
 if ($cron_user eq "root" && $fetchmail_config) {
 	defined(getpwnam($in{'user'})) || &error($text{'cron_euser'});
-	$cmd .= " --user $in{'user'}";
+	$cmd .= " --user ".quotemeta($in{'user'});
 	}
 
 if ($job && $in{'enabled'}) {
diff --git a/fetchmail/save_global.cgi b/fetchmail/save_global.cgi
index 422848445..c1a1468a7 100755
--- a/fetchmail/save_global.cgi
+++ b/fetchmail/save_global.cgi
@@ -51,9 +51,9 @@ if ($found) {
 else {
 	&create_poll($poll, $file);
 	if ($in{'user'} && $< == 0) {
-		&system_logged("chown $in{'user'} $file");
+		&system_logged("chown ".quotemeta($in{'user'})." ".quotemeta($file));
 		}
-	&system_logged("chmod 700 $file");
+	&system_logged("chmod 700 ".quotemeta($file));
 	}
 &unlock_file($file);
 &webmin_log("global", undef, $config{'config_file'} ? $file : $in{'user'},
diff --git a/fetchmail/save_poll.cgi b/fetchmail/save_poll.cgi
index 390c279be..598b4903c 100755
--- a/fetchmail/save_poll.cgi
+++ b/fetchmail/save_poll.cgi
@@ -101,9 +101,9 @@ else {
 		&create_poll($poll, $file);
 		if ($in{'user'} && $< == 0) {
 			local @uinfo = getpwnam($in{'user'});
-			&system_logged("chown $uinfo[2]:$uinfo[3] $file");
+			&system_logged("chown $uinfo[2]:$uinfo[3] ".quotemeta($file));
 			}
-		&system_logged("chmod 700 $file");
+		&system_logged("chmod 700 ".quotemeta($file));
 		}
 	else {
 		&modify_poll($poll, $file);
diff --git a/fetchmail/start.cgi b/fetchmail/start.cgi
index 5f5cba00a..1e21b0642 100755
--- a/fetchmail/start.cgi
+++ b/fetchmail/start.cgi
@@ -13,17 +13,21 @@ if ($config{'start_cmd'}) {
 	}
 else {
 	$in{'interval'} =~ /^\d+$/ || &error($text{'start_einterval'});
-	$mda = " -m '$config{'mda_command'}'" if ($config{'mda_command'});
+	$mda = " -m ".quotemeta($config{'mda_command'}) if ($config{'mda_command'});
+	my $qinterval = quotemeta($in{'interval'});
+	my $qconfig_file = quotemeta($config{'config_file'});
 	if ($< == 0) {
 		if ($config{'daemon_user'} eq 'root') {
-			$out = &backquote_logged("$config{'fetchmail_path'} -d $in{'interval'} -f $config{'config_file'} $mda 2>&1");
+			$out = &backquote_logged("$config{'fetchmail_path'} -d $qinterval -f $qconfig_file $mda 2>&1");
 			}
 		else {
-			$out = &backquote_logged("su - '$config{'daemon_user'}' -c '$config{'fetchmail_path'} -d $in{'interval'} -f $config{'config_file'} $mda' 2>&1");
+			my $qdaemon_user = quotemeta($config{'daemon_user'});
+			my $daemon_cmd = "$config{'fetchmail_path'} -d $qinterval -f $qconfig_file $mda";
+			$out = &backquote_logged("su - $qdaemon_user -c ".quotemeta($daemon_cmd)." 2>&1");
 			}
 		}
 	else {
-		$out = &backquote_logged("$config{'fetchmail_path'} -d $in{'interval'} $mda 2>&1");
+		$out = &backquote_logged("$config{'fetchmail_path'} -d $qinterval $mda 2>&1");
 		}
 	}
 if ($?) {
diff --git a/fetchmail/stop.cgi b/fetchmail/stop.cgi
index 62402b5a2..0d9cd07e0 100755
--- a/fetchmail/stop.cgi
+++ b/fetchmail/stop.cgi
@@ -16,7 +16,8 @@ elsif ($< == 0) {
 		$out = &backquote_logged("$config{'fetchmail_path'} -q 2>&1");
 		}
 	else {
-		$out = &backquote_logged("su - '$config{'daemon_user'}' -c '$config{'fetchmail_path'} -q' 2>&1");
+		my $qdaemon_user = quotemeta($config{'daemon_user'});
+		$out = &backquote_logged("su - $qdaemon_user -c ".quotemeta("$config{'fetchmail_path'} -q")." 2>&1");
 		}
 	}
 else {