1 files changed, 35 insertions, 1 deletions
diff --git a/vendor/smarty/smarty/libs/plugins/shared.mb_str_replace.php b/vendor/smarty/smarty/libs/plugins/shared.mb_str_replace.php
index 226d9035d..7e85f7aae 100644
--- a/vendor/smarty/smarty/libs/plugins/shared.mb_str_replace.php
+++ b/vendor/smarty/smarty/libs/plugins/shared.mb_str_replace.php
@@ -44,9 +44,43 @@ if (!function_exists('smarty_mb_str_replace')) {
                 }
             }
         } else {
-            $parts = mb_split(preg_quote($search), $subject) ?: array();
+            $mb_reg_charset = mb_regex_encoding();
+            // Check if mbstring regex is using UTF-8
+            $reg_is_unicode = !strcasecmp($mb_reg_charset, "UTF-8");
+            if(!$reg_is_unicode) {
+                // ...and set to UTF-8 if not
+                mb_regex_encoding("UTF-8");
+            }
+
+            // See if charset used by Smarty is matching one used by regex...
+            $current_charset = mb_regex_encoding();
+            $convert_result = (bool)strcasecmp(Smarty::$_CHARSET, $current_charset);
+            if($convert_result) {
+                // ...convert to it if not.
+                $subject = mb_convert_encoding($subject, $current_charset, Smarty::$_CHARSET);
+                $search = mb_convert_encoding($search, $current_charset, Smarty::$_CHARSET);
+                $replace = mb_convert_encoding($replace, $current_charset, Smarty::$_CHARSET);
+            }
+
+            $parts = mb_split(preg_quote($search), $subject ?? "") ?: array();
+            // If original regex encoding was not unicode...
+            if(!$reg_is_unicode) {
+                // ...restore original regex encoding to avoid breaking the system.
+                mb_regex_encoding($mb_reg_charset);
+            }
+            if($parts === false) {
+                // This exception is thrown if call to mb_split failed.
+                // Usually it happens, when $search or $replace are not valid for given mb_regex_encoding().
+                // There may be other cases for it to fail, please file an issue if you find a reproducible one.
+                throw new SmartyException("Source string is not a valid $current_charset sequence (probably)");
+            }
+
             $count = count($parts) - 1;
             $subject = implode($replace, $parts);
+            // Convert results back to charset used by Smarty, if needed.
+            if($convert_result) {
+                $subject = mb_convert_encoding($subject, Smarty::$_CHARSET, $current_charset);
+            }
         }
         return $subject;
     }