diff --git a/filter/mathjaxloader/db/upgrade.php b/filter/mathjaxloader/db/upgrade.php
index 58237981771d3..18ee85fc575d9 100644
--- a/filter/mathjaxloader/db/upgrade.php
+++ b/filter/mathjaxloader/db/upgrade.php
@@ -55,5 +55,17 @@ function xmldb_filter_mathjaxloader_upgrade($oldversion) {
     // Automatically generated Moodle v3.9.0 release upgrade line.
     // Put any upgrade step following this.
 
+    if ($oldversion < 2021052501) {
+        // Update CDN url.
+        $originalurl = 'https://cdn.jsdelivr.net/npm/mathjax@2.7.8/MathJax.js';
+        $newurl = 'https://cdn.jsdelivr.net/npm/mathjax@2.7.9/MathJax.js';
+        $currenturl = get_config('filter_mathjaxloader', 'httpsurl');
+        if ($currenturl == $originalurl) {
+            set_config('httpsurl', $newurl, 'filter_mathjaxloader');
+        }
+
+        upgrade_plugin_savepoint(true, 2021052501, 'filter', 'mathjaxloader');
+    }
+
     return true;
 }
diff --git a/filter/mathjaxloader/readme_moodle.txt b/filter/mathjaxloader/readme_moodle.txt
index 32a4fc0006731..38ba21fb25211 100644
--- a/filter/mathjaxloader/readme_moodle.txt
+++ b/filter/mathjaxloader/readme_moodle.txt
@@ -1,7 +1,7 @@
 Description of MathJAX library integration in Moodle
 ====================================================
 
-* Default MathJax version: 2.7.8
+* Default MathJax version: 2.7.9
 * License: Apache 2.0
 * Source: https://www.mathjax.org/
 
@@ -21,5 +21,7 @@ Upgrading the default MathJax version
 Changes
 -------
 
+* Updated to the 2.7.9 version. See MDL-70317 for details.
+
 * The MathJax 2.7.2 seems to have a possible security issue, the CDN default value have been
 updated to point to the recommended 2.7.8 version. See MDL-68430 for details.
diff --git a/filter/mathjaxloader/settings.php b/filter/mathjaxloader/settings.php
index 06ceee8f1029e..d3f65130bfb22 100644
--- a/filter/mathjaxloader/settings.php
+++ b/filter/mathjaxloader/settings.php
@@ -33,7 +33,7 @@
     $item = new admin_setting_configtext('filter_mathjaxloader/httpsurl',
                                          new lang_string('httpsurl', 'filter_mathjaxloader'),
                                          new lang_string('httpsurl_help', 'filter_mathjaxloader'),
-                                         'https://cdn.jsdelivr.net/npm/mathjax@2.7.8/MathJax.js',
+                                         'https://cdn.jsdelivr.net/npm/mathjax@2.7.9/MathJax.js',
                                          PARAM_RAW);
     $settings->add($item);
 
diff --git a/filter/mathjaxloader/version.php b/filter/mathjaxloader/version.php
index 73af6ff24942a..38cda9b202caa 100644
--- a/filter/mathjaxloader/version.php
+++ b/filter/mathjaxloader/version.php
@@ -24,6 +24,6 @@
 
 defined('MOODLE_INTERNAL') || die();
 
-$plugin->version  = 2021052500;
+$plugin->version  = 2021052501;
 $plugin->requires = 2021052500;  // Requires this Moodle version.
 $plugin->component= 'filter_mathjaxloader';