Index: wp-includes/formatting.php
IDEA additional info:
Subsystem: com.intellij.openapi.diff.impl.patch.CharsetEP
<+>UTF-8
===================================================================
--- wp-includes/formatting.php	(revision c5d9d5cc1824fa04e6200bb2706548a46b87a44f)
+++ wp-includes/formatting.php	(revision )
@@ -1772,7 +1772,7 @@
 		 * @param string $filename     Sanitized filename.
 		 * @param string $filename_raw The filename prior to sanitization.
 		 */
-		return apply_filters( 'sanitize_file_name', $filename, $filename_raw );
+		return apply_filters( 'sanitize_file_name', preg_replace( "/[^a-z0-9\-.]/", "", $filename ), $filename_raw );
 	}
 
 	// Process multiple extensions
@@ -1802,7 +1802,7 @@
 	}
 	$filename .= '.' . $extension;
 	/** This filter is documented in wp-includes/formatting.php */
-	return apply_filters('sanitize_file_name', $filename, $filename_raw);
+	return apply_filters( 'sanitize_file_name', preg_replace( "/[^a-z0-9\-.]/", "", $filename ), $filename_raw );
 }
 
 /**