diff --git a/phpBB/includes/search/fulltext_sphinx.php b/phpBB/includes/search/fulltext_sphinx.php
index 6c66499d21..7304e70ff8 100644
--- a/phpBB/includes/search/fulltext_sphinx.php
+++ b/phpBB/includes/search/fulltext_sphinx.php
@@ -879,7 +879,7 @@ class phpbb_search_fulltext_sphinx
 		</dl>
 		<dl>
 			<dt><label for="fulltext_sphinx_config_file">' . $this->user->lang['FULLTEXT_SPHINX_CONFIG_FILE'] . $this->user->lang['COLON'] . '</label><br /><span>' . $this->user->lang['FULLTEXT_SPHINX_CONFIG_FILE_EXPLAIN'] . '</span></dt>
-			<dd>' . (($this->config_generate()) ? '<textarea readonly="readonly" rows="6" id="sphinx_config_data">' . $this->config_file_data . '</textarea>' : $this->config_file_data) . '</dd>
+			<dd>' . (($this->config_generate()) ? '<textarea readonly="readonly" rows="6" id="sphinx_config_data">' . htmlspecialchars($this->config_file_data) . '</textarea>' : $this->config_file_data) . '</dd>
 		<dl>
 		';