These things are getting more and more popular now. Great article by brother By Abu Eesa Niamatullah. Worth reading:
– smoking cigarettes and other tobacco products is forbidden
– “vaping” or inhaling vapour from an e-cigarette with nicotine in it, is forbidden
– smoking and ingesting marijuana and cannabis products is forbidden
– vaping “marijuana” synthetic cannabinoid e-liquid is forbidden
– vaping substances which have no nicotine or marijuana, should be avoided
And Allah knows best.