Vietnam's Public Security Ministry, which is responsible for the police and internal security, has purchased the software, according to Israeli newspaper Haaretz.
In a recent interview with the business daily Globes, the company's CEO, Yossi Carmil, claimed the surveillance firm had developed technological equipment that prevents its tools from landing into "the wrong hands".
However, an investigation conducted by Israeli human rights lawyer Eitay Mack, exposed how Vietnamese authorities used the spyware in 2018 to detain a citizen, who participated in a prank which involved displaying the flag of South Vietnam which is banned in the country, for up to five years. His motorcycle and phone were also confiscated by the state.
In an open letter published on Tuesday to the US Securities and Exchange Commission (SEC) and investors, digital rights groups, including Access Now, the Electronic Frontier Foundation, Privacy International, urged all "parties to halt this deal until Cellebrite demonstrates that it has taken sufficient measures to comply with human rights".
It further stated Cellebrite's sales of surveillance tools were still "enabling detentions, prosecutions, and harassment of journalists, civil rights activists, dissidents, and minorities around the world."
Rights lawyer Mack noted how Vietnam is also licensed to produce Israel's Tavor and Galil ACE rifles and added a long list of high-level visits and meetings to the country, including by senior Defense Ministry officials, former Prime Minister Benjamin Netanyahu and former President Reuven Rivlin.
In response, a Cellebrite spokesperson said the company has "strict licensing policies and restrictions that govern how customers may utilize our technology" and considers "a potential customer's human rights record and anti-corruption policies."
The company's SEC filing says it does not do business with Belarus, China, Hong Kong, Macau, Russia and Venezuela, "partially due to concerns regarding human rights and data security."