But sources have now confirmed to the BBC that only two of the men who stood trial were convicted.
The secrecy surrounding the trial, which was held behind closed doors, raised suspicions over its validity.
The court judgement – seen for the first time on Friday more than a month after the trial – claims that the two men convicted were those who shot Ms Yousafzai in 2012.
It was previously thought that both the gunmen and the man who ordered the attack had fled to Afghanistan.
Muneer Ahmed, a spokesman for the Pakistani High Commission in London, said on Friday that the eight men were acquitted because of a lack of evidence.
Saleem Marwat, the district police chief in Swat, Pakistan, separately confirmed that only two men had been convicted.
Mr Ahmed claimed that the original court judgement made it clear only two men had been convicted and blamed the confusion on misreporting.
But Sayed Naeem, a public prosecutor in Swat, told the Associated Press news agency after the trial: “Each militant got 25 years in jail. It is life in prison for the 10 militants who were tried by an anti-terrorist court.” In Pakistan, a life sentence is 25 years.
The acquittals emerged after reporters from the London-based Daily Mirror attempted to locate the 10 convicted men in prisons in Pakistan.
The whereabouts of the eight acquitted men is not known.
The trial was held at a military facility rather than a court and was shrouded in secrecy, a Pakistani security source told the BBC. Anti-terrorism trials in Pakistan are not open to the public.
Pakistani authorities did not make the judgement available at any stage, nor did they correct the reports over the past two months that 10 men had been convicted.
The announcement of the convictions in April took many by surprise. No journalists had been made aware that the trial was taking place.
The authorities did not say when and where the men had been arrested or how they were linked to the attack, or explain the charges against them.
It didn’t take long for the news to spread around Pakistan’s fiercely competitive media, and then the world: 10 men had been convicted over the murder of Malala Yusafzai and sentenced to life.
The only problem? It wasn’t true. Only two of the 10 were found guilty. Was it a calculated leak? Or did officials simply neglect to correct an error that made good PR?
When the news first broke, an army spokesman told journalists he would be issuing a statement, but later he changed his mind. By then the news had been on TV for several hours.
The Associated Press quoted a public prosecutor as saying 10 men had been sentenced to life. The prosecutor said nothing for more than a month – only now he denies speaking to the reporter.
Amid the confusion over how the false information spread and why, what we do know is that Pakistan was under pressure. Malala had been awarded the Nobel prize but no-one had been brought to justice, and Pakistan was keen to improve troubled ties with the US, UK and Afghanistan.
And we know that, even if Pakistani officials did not purposefully spread misinformation, they allowed it to stand.
Ms Yousafzai, who is now 17, was targeted by Taliban gunmen while she was travelling home from school in the town of Mingora.
The gunmen boarded a bus and asked for her by name before shooting her in the head.
She was treated for her injuries in the UK and currently lives in Birmingham with her family. They are unable to return to Pakistan because of death threats from the Taliban.
Ms Yousafzai was targeted after campaigning for education rights for girls. She also wrote an anonymous blog for the BBC’s Urdu service, describing life under the Taliban.
Pakistan’s mountainous Swat valley, where she lived with her family, was overrun by the Taliban between 2007 and 2009.