diff --git a/NEWS b/NEWS
index 4c9bc776f51..5fd1ce39d55 100644
--- a/NEWS
+++ b/NEWS
@@ -13,6 +13,9 @@ PHP                                                                        NEWS
   . Fixed GH-18695 (zend_ast_export() - float number is not preserved).
     (Oleg Efimov)
 
+- Curl:
+  . Fix memory leak when setting a list via curl_setopt fails. (nielsdos)
+
 - Date:
   . Fix leaks with multiple calls to DatePeriod iterator current(). (nielsdos)
 
diff --git a/ext/curl/interface.c b/ext/curl/interface.c
index 4bf0c84c67a..3b13744abce 100644
--- a/ext/curl/interface.c
+++ b/ext/curl/interface.c
@@ -2166,12 +2166,14 @@ static zend_result _php_curl_setopt(php_curl *ch, zend_long option, zval *zvalue
 			ZEND_HASH_FOREACH_VAL(ph, current) {
 				ZVAL_DEREF(current);
 				val = zval_get_tmp_string(current, &tmp_val);
-				slist = curl_slist_append(slist, ZSTR_VAL(val));
+				struct curl_slist *new_slist = curl_slist_append(slist, ZSTR_VAL(val));
 				zend_tmp_string_release(tmp_val);
-				if (!slist) {
+				if (!new_slist) {
+					curl_slist_free_all(slist);
 					php_error_docref(NULL, E_WARNING, "Could not build curl_slist");
 					return FAILURE;
 				}
+				slist = new_slist;
 			} ZEND_HASH_FOREACH_END();
 
 			if (slist) {