In one case, WWF staff are said to have signed off on an alleged proposal to kill trespassers at a wildlife park in India.
Survival International (SI), a UK-based organisation that aims to protect vulnerable indigenous populations around the world, has previously accused the WWF of "green colonialism" for allegedly helping to dispossess native people of land for WWF-backed national parks and tiger reserves.
A human rights complaint launched by SI against the WWF on behalf of the hunter-gatherer Baka people in Cameroon was examined by the Organisation for Economic Co-operation and Development (OECD) in 2017, however SI later withdrew from the process.
"This is the scandal that WWF has been covering up for decades," said SI director Stephen Corry in response to the Buzzfeed story this morning.
"Its name and logo are for many tribal people synonymous with violence, persecution and fear."
The WWF says it has commissioned London law firm Kingsley Napley to look into the claims.
"At the heart of WWF's work are places and the people who live in them. Respect for human rights is at the core of our mission," a spokesperson said in a statement.
"We take any allegation seriously and are commissioning an independent review to look into the cases raised in the story. We have asked BuzzFeed to share all evidence it has obtained to support these claims, to help inform and strengthen this review."
The accusations threaten to harm the reputation of the global charity that relies heavily on donations to carry out its work and has a long list of prominent backers.
Prince Phillip, who is President Emeritus of WWF, helped found the charity and served as WWF International president from 1981 to 1996. Prince Charles and David Attenborough are also patrons of the charity.
WWF has been contacted for comment.