diff --git a/src/api/system.c b/src/api/system.c
index fbb917ee..0215a564 100644
--- a/src/api/system.c
+++ b/src/api/system.c
@@ -335,10 +335,10 @@ static int f_sleep(lua_State *L) {
 static int f_exec(lua_State *L) {
   size_t len;
   const char *cmd = luaL_checklstring(L, 1, &len);
-  char *buf = malloc(len + 16);
+  char *buf = malloc(len + 32);
   if (!buf) { luaL_error(L, "buffer allocation failed"); }
 #if _WIN32
-  sprintf(buf, "cmd /c %s", cmd);
+  sprintf(buf, "cmd /c \"%s\"", cmd);
   WinExec(buf, SW_HIDE);
 #else
   sprintf(buf, "%s &", cmd);