If players create an artificial Corruption biome in a Crimson world, they may obtain Cursed Flames. One might simply bring it from another world as a solution. As of the 1.4 update, it is possible to obtain Cursed Flames in a Crimson world without the use of creating another world. To do so, one must buy Corrupt Seeds from the Dryad in Hardmode while in a Graveyard and let it spread anywhere in the world to create an artificial Corrupt biome, giving access to Cursed Flames.
Trivia[]
The Cursed Flame may be based on Greek Fire, a substance from the Eastern Romans that was able to burn almost anywhere, and was used in naval warfare.
It also may be based on the cursed green flames from The Festival, a short story by H. P. Lovecraft.