diff --git a/filter/tex/latex.php b/filter/tex/latex.php
index d626a9f0bbf..a1966da6212 100644
--- a/filter/tex/latex.php
+++ b/filter/tex/latex.php
@@ -94,6 +94,7 @@
             if (empty($pathlatex)) {
                 return false;
             }
+            $pathlatex = escapeshellarg(trim($pathlatex, " '\""));
 
             $doc = $this->construct_latex_document( $formula, $fontsize );
 
@@ -114,15 +115,15 @@
             fclose( $fh );
 
             // run latex on document
-            $command = "{$pathlatex} --interaction=nonstopmode --halt-on-error $tex";
+            $command = "$pathlatex --interaction=nonstopmode --halt-on-error $tex";
             chdir( $this->temp_dir );
             if ($this->execute($command, $log)) { // It allways False on Windows
 //                return false;
             }
 
             // run dvips (.dvi to .ps)
-            $pathdvips = get_config('filter_tex', 'pathdvips');
-            $command = "{$pathdvips} -E $dvi -o $ps";
+            $pathdvips = escapeshellarg(trim(get_config('filter_tex', 'pathdvips'), " '\""));
+            $command = "$pathdvips -E $dvi -o $ps";
             if ($this->execute($command, $log )) {
                 return false;
             }
@@ -134,11 +135,11 @@
                 $bg_opt = "";
             }
             if ($convertformat == 'svg') {
-                $pathdvisvgm = get_config('filter_tex', 'pathdvisvgm');
-                $command = "{$pathdvisvgm} -E $ps -o $img";
+                $pathdvisvgm = escapeshellarg(trim(get_config('filter_tex', 'pathdvisvgm'), " '\""));
+                $command = "$pathdvisvgm -E $ps -o $img";
             } else {
-                $pathconvert = get_config('filter_tex', 'pathconvert');
-                $command = "{$pathconvert} -density $density -trim $bg_opt $ps $img";
+                $pathconvert = escapeshellarg(trim(get_config('filter_tex', 'pathconvert'), " '\""));
+                $command = "$pathconvert -density $density -trim $bg_opt $ps $img";
             }
             if ($this->execute($command, $log )) {
                 return false;
diff --git a/filter/tex/lib.php b/filter/tex/lib.php
index f48bca8aa31..4aad3ec543f 100644
--- a/filter/tex/lib.php
+++ b/filter/tex/lib.php
@@ -125,9 +125,10 @@ function filter_tex_updatedcallback($name) {
         return;
     }
 
-    $pathdvips = get_config('filter_tex', 'pathdvips');
-    $pathconvert = get_config('filter_tex', 'pathconvert');
-    $pathdvisvgm = get_config('filter_tex', 'pathdvisvgm');
+    $pathlatex = trim($pathlatex, " '\"");
+    $pathdvips = trim(get_config('filter_tex', 'pathdvips'), " '\"");
+    $pathconvert = trim(get_config('filter_tex', 'pathconvert'), " '\"");
+    $pathdvisvgm = trim(get_config('filter_tex', 'pathdvisvgm'), " '\"");
 
     $supportedformats = array('gif');
     if ((is_file($pathlatex) && is_executable($pathlatex)) &&
diff --git a/filter/tex/settings.php b/filter/tex/settings.php
index fb0fcdfff4a..e0d5ddce68f 100644
--- a/filter/tex/settings.php
+++ b/filter/tex/settings.php
@@ -55,9 +55,22 @@ if ($ADMIN->fulltree) {
     } else if (PHP_OS=='WINNT' or PHP_OS=='WIN32' or PHP_OS=='Windows') {
         // note: you need Ghostscript installed (standard), miktex (standard)
         // and ImageMagick (install at c:\ImageMagick)
-        $default_filter_tex_pathlatex   = "\"c:\\texmf\\miktex\\bin\\latex.exe\" ";
-        $default_filter_tex_pathdvips   = "\"c:\\texmf\\miktex\\bin\\dvips.exe\" ";
-        $default_filter_tex_pathconvert = "\"c:\\imagemagick\\convert.exe\" ";
+        $default_filter_tex_pathlatex   = "c:\\texmf\\miktex\\bin\\latex.exe";
+        $default_filter_tex_pathdvips   = "c:\\texmf\\miktex\\bin\\dvips.exe";
+        $default_filter_tex_pathdvisvgm   = "c:\\texmf\\miktex\\bin\\dvisvgm.exe";
+        $default_filter_tex_pathconvert = "c:\\imagemagick\\convert.exe";
+    }
+
+    $pathlatex = get_config('filter_tex', 'pathlatex');
+    $pathdvips = get_config('filter_tex', 'pathdvips');
+    $pathconvert = get_config('filter_tex', 'pathconvert');
+    $pathdvisvgm = get_config('filter_tex', 'pathdvisvgm');
+    if (strrpos($pathlatex . $pathdvips . $pathconvert . $pathdvisvgm, '"') or
+            strrpos($pathlatex . $pathdvips . $pathconvert . $pathdvisvgm, "'")) {
+        set_config('pathlatex', trim($pathlatex, " '\""), 'filter_tex');
+        set_config('pathdvips', trim($pathdvips, " '\""), 'filter_tex');
+        set_config('pathconvert', trim($pathconvert, " '\""), 'filter_tex');
+        set_config('pathdvisvgm', trim($pathdvisvgm, " '\""), 'filter_tex');
     }
 
     $items[] = new admin_setting_configexecutable('filter_tex/pathlatex', get_string('pathlatex', 'filter_tex'), '', $default_filter_tex_pathlatex);
diff --git a/filter/tex/texdebug.php b/filter/tex/texdebug.php
index b82e97c1817..ad28cbc24f7 100644
--- a/filter/tex/texdebug.php
+++ b/filter/tex/texdebug.php
@@ -200,28 +200,28 @@
         // first check if it is likely to work at all
         $output .= "<h3>Checking executables</h3>\n";
         $executablesexist = true;
-        $pathlatex = get_config('filter_tex', 'pathlatex');
+        $pathlatex = trim(get_config('filter_tex', 'pathlatex'), " '\"");
         if (is_file($pathlatex)) {
             $output .= "latex executable ($pathlatex) is readable<br />\n";
         } else {
             $executablesexist = false;
             $output .= "<b>Error:</b> latex executable ($pathlatex) is not readable<br />\n";
         }
-        $pathdvips = get_config('filter_tex', 'pathdvips');
+        $pathdvips = trim(get_config('filter_tex', 'pathdvips'), " '\"");
         if (is_file($pathdvips)) {
             $output .= "dvips executable ($pathdvips) is readable<br />\n";
         } else {
             $executablesexist = false;
             $output .= "<b>Error:</b> dvips executable ($pathdvips) is not readable<br />\n";
         }
-        $pathconvert = get_config('filter_tex', 'pathconvert');
+        $pathconvert = trim(get_config('filter_tex', 'pathconvert'), " '\"");
         if (is_file($pathconvert)) {
             $output .= "convert executable ($pathconvert) is readable<br />\n";
         } else {
             $executablesexist = false;
             $output .= "<b>Error:</b> convert executable ($pathconvert) is not readable<br />\n";
         }
-        $pathdvisvgm = get_config('filter_tex', 'pathdvisvgm');
+        $pathdvisvgm = trim(get_config('filter_tex', 'pathdvisvgm'), " '\"");
         if (is_file($pathdvisvgm)) {
             $output .= "dvisvgm executable ($pathdvisvgm) is readable<br />\n";
         } else {
@@ -252,17 +252,21 @@
         chdir($latex->temp_dir);
 
         // step 1: latex command
+        $pathlatex = escapeshellarg($pathlatex);
         $cmd = "$pathlatex --interaction=nonstopmode --halt-on-error $tex";
         $output .= execute($cmd);
 
         // step 2: dvips command
+        $pathdvips = escapeshellarg($pathdvips);
         $cmd = "$pathdvips -E $dvi -o $ps";
         $output .= execute($cmd);
 
         // Step 3: Set convert or dvisvgm command.
         if ($convertformat == 'svg') {
+            $pathdvisvgm = escapeshellarg($pathdvisvgm);
             $cmd = "$pathdvisvgm -E $ps -o $img";
         } else {
+            $pathconvert = escapeshellarg($pathconvert);
             $cmd = "$pathconvert -density 240 -trim $ps $img ";
         }
         $output .= execute($cmd);