diff --git a/http.c b/http.c
index 027a86d..5f34816 100644
--- a/http.c
+++ b/http.c
@@ -150,7 +150,7 @@
 
 static struct curl_slist *pragma_header;
 static struct curl_slist *no_pragma_header;
-static struct curl_slist *extra_http_headers;
+static struct string_list extra_http_headers = STRING_LIST_INIT_DUP;
 
 static struct active_request_slot *active_queue_head;
 
@@ -414,11 +414,9 @@
 		if (!value) {
 			return config_error_nonbool(var);
 		} else if (!*value) {
-			curl_slist_free_all(extra_http_headers);
-			extra_http_headers = NULL;
+			string_list_clear(&extra_http_headers, 0);
 		} else {
-			extra_http_headers =
-				curl_slist_append(extra_http_headers, value);
+			string_list_append(&extra_http_headers, value);
 		}
 		return 0;
 	}
@@ -1202,8 +1200,7 @@
 #endif
 	curl_global_cleanup();
 
-	curl_slist_free_all(extra_http_headers);
-	extra_http_headers = NULL;
+	string_list_clear(&extra_http_headers, 0);
 
 	curl_slist_free_all(pragma_header);
 	pragma_header = NULL;
@@ -1627,10 +1624,11 @@
 
 struct curl_slist *http_copy_default_headers(void)
 {
-	struct curl_slist *headers = NULL, *h;
+	struct curl_slist *headers = NULL;
+	const struct string_list_item *item;
 
-	for (h = extra_http_headers; h; h = h->next)
-		headers = curl_slist_append(headers, h->data);
+	for_each_string_list_item(item, &extra_http_headers)
+		headers = curl_slist_append(headers, item->string);
 
 	return headers;
 }