diff --git a/CRM/Utils/System/Backdrop.php b/CRM/Utils/System/Backdrop.php
index 88ab5c43863a..a55dd9b126ed 100644
--- a/CRM/Utils/System/Backdrop.php
+++ b/CRM/Utils/System/Backdrop.php
@@ -606,6 +606,11 @@ public function loadBootStrap($params = array(), $loadUser = TRUE, $throwError =
    * @inheritDoc
    */
   public function cmsRootPath($scriptFilename = NULL) {
+    global $civicrm_paths;
+    if (!empty($civicrm_paths['cms.root']['path'])) {
+      return $civicrm_paths['cms.root']['path'];
+    }
+
     $cmsRoot = NULL;
     $valid = NULL;
 
diff --git a/CRM/Utils/System/Drupal6.php b/CRM/Utils/System/Drupal6.php
index 54a3d0c007ed..aae0fbfe1682 100644
--- a/CRM/Utils/System/Drupal6.php
+++ b/CRM/Utils/System/Drupal6.php
@@ -543,6 +543,12 @@ public function cmsRootPath($scriptFilename = NULL) {
       // drush anyway takes care of multisite install etc
       return drush_get_context('DRUSH_DRUPAL_ROOT');
     }
+
+    global $civicrm_paths;
+    if (!empty($civicrm_paths['cms.root']['path'])) {
+      return $civicrm_paths['cms.root']['path'];
+    }
+
     // CRM-7582
     $pathVars = explode('/',
       str_replace('//', '/',
diff --git a/CRM/Utils/System/Drupal8.php b/CRM/Utils/System/Drupal8.php
index 8d931aa04560..4e5a44243faf 100644
--- a/CRM/Utils/System/Drupal8.php
+++ b/CRM/Utils/System/Drupal8.php
@@ -483,6 +483,11 @@ public function loadBootStrap($params = array(), $loadUser = TRUE, $throwError =
    * @return NULL|string
    */
   public function cmsRootPath($path = NULL) {
+    global $civicrm_paths;
+    if (!empty($civicrm_paths['cms.root']['path'])) {
+      return $civicrm_paths['cms.root']['path'];
+    }
+
     if (defined('DRUPAL_ROOT')) {
       return DRUPAL_ROOT;
     }
diff --git a/CRM/Utils/System/Joomla.php b/CRM/Utils/System/Joomla.php
index 8162ac8a615c..5f3995c3d030 100644
--- a/CRM/Utils/System/Joomla.php
+++ b/CRM/Utils/System/Joomla.php
@@ -694,6 +694,11 @@ public function getLoginDestination(&$form) {
    *   local file system path to CMS root, or NULL if it cannot be determined
    */
   public function cmsRootPath() {
+    global $civicrm_paths;
+    if (!empty($civicrm_paths['cms.root']['path'])) {
+      return $civicrm_paths['cms.root']['path'];
+    }
+
     list($url, $siteName, $siteRoot) = $this->getDefaultSiteSettings();
     $includePath = "$siteRoot/libraries/cms/version";
     if (file_exists("$includePath/version.php")) {
diff --git a/CRM/Utils/System/WordPress.php b/CRM/Utils/System/WordPress.php
index d49c7d77b470..bfab40510f32 100644
--- a/CRM/Utils/System/WordPress.php
+++ b/CRM/Utils/System/WordPress.php
@@ -481,6 +481,11 @@ public function validInstallDir($dir) {
    *   local file system path to CMS root, or NULL if it cannot be determined
    */
   public function cmsRootPath() {
+    global $civicrm_paths;
+    if (!empty($civicrm_paths['cms.root']['path'])) {
+      return $civicrm_paths['cms.root']['path'];
+    }
+
     $cmsRoot = $valid = NULL;
     if (defined('CIVICRM_CMSDIR')) {
       if ($this->validInstallDir(CIVICRM_CMSDIR)) {