Courtney Love believes Kermit the Frog and his gang of Muppet friends "raped" the memory of her late husband Kurt Cobain -- by bastardizing Nirvana's "Smells Like Teen Spirit" in their 2011 movie ... without her permission.
Courtney says she has the absolute power to approve or nix the use of Kurt's music for commercial purposes, and she never gave the OK for the 2 companies to use the song for the 2011 Muppets movie.
But there's another side to this ... We're told Courtney sold off half of her rights to Kurt's music to a company called Primary Wave Music. And there's more ... Courtney also gave Primary Wave the exclusive right to distribute Nirvana's entire catalog.
As far as "Smells Like Teen Spirit" goes ... not only did Primary Wave approve the use in the Muppet's movie, they got permission from the two surviving Nirvana members -- Dave Grohl and Krist Novoselic. And Dave is even in the movie.
But it's not all that bad for Courtney. We're told a chunk of the profits from songs in the catalog go to Courtney and her daughter, Frances Bean.