Find charset in HTML meta tags if not specified in content-type header (#1488125)

program/include/rcube_imap.php

@@ -2396,7 +2396,11 @@ class rcube_imap
 
            if (!$skip_charset_conv) {
                 if (!$o_part->charset || strtoupper($o_part->charset) == 'US-ASCII') {
-                    $o_part->charset = $this->default_charset;
+                    // try to extract charset information from HTML meta tag (#1488125)
+                    if ($o_part->ctype_secondary == 'html' && preg_match('/<meta[^>]+charset=([a-z0-9-]+)/i', $body, $m))
+                        $o_part->charset = strtoupper($m[1]);
+                    else
+                        $o_part->charset = $this->default_charset;
                 }
                 $body = rcube_charset_convert($body, $o_part->charset);
             }