The leaks began circulating on social media on Thursday at around 6.45am Ugandan time.
"This one was just a message which has been shared among people," Henry Alanga, a Bachelor of social sciences student at Makerere University told RFI, after receiving a Whatsapp message.
"It said 'If you have anyone sitting the paper you can assist.' In other places, there are some headteachers who have been complaining that they've been getting messages from anonymous people asking them for some fee that can be charged and they be given the papers."
The fee varied between 200,000 and 500,000 Ugandan shillings (50-120 euros).
Those able to pay were granted access to this year's O-level papers in biology, chemistry and Christian religious education a couple of hours before examination time.
For Alanga, the news felt like déjà-vu.
"Me personally, I got a leakage for the same biology paper [in 2011] like a day before the paper. We didn't believe it because our school was in the rural area and the internet didn't work so well then. But after the paper we found it was true."
Exam board under scrutiny
"It’s unfortunate," former Uneb chairman Fagil Mandy commented. "I hope the body will be able to block any other leakages, so that the people can move on."
Asked whether the leaks had brought the examination board into disrepute, he replied: "I think they’ve been trying their best. All I can say really is let people not get worried. I know the leakage means a lot to some people and it should."
For Makerere University lecturer Adolf Mbaine, however, the exam board's best is not good enough.
"Leaked examination papers by the Uganda National Examinations Body has been a problem for many years now," he told RFI.
"It is damaging to the education system because eventually you have students who have very high grades but are not good enough. It also casts doubts on the qualifications of Ugandans who are either going to study or work abroad, if you don't have a fool-proof examinations system."
Exam leaks are just one of the challenges facing Uganda's education system, says education expert, Bwengye Stephen.
"We are producing students who don't have jobs around," he told RFI. "We are training people who cannot be absorbed by the economy you know. We have to change so that we are equipping people with skills that are required in the economy."
For Mbaine this mismatch is linked to a failure by Uneb to ensure credible exams.
That led Makerere University to introduce its own pre-entry exams for future students last year.
But its attempts to do so were blocked by Uneb, which has been hit by accusations that papers have been leaked to private schools for profit.
"Their students all pass very high, but they're given basic pre-entry exams and they can't pass them," comments Mbaine, who has called for a complete overhaul of the examinations board.
“Of course this is a malpractice, thieves and corrupt people, you know, they’re out to make a profit out of a hot issue," Fagil Mandy reckons.
However both former and current exam officials, seem confident enough in the system that the timetable for the remaining papers has not been changed, and there's to be no overhaul of the tests that students took Thursday.
Uneb has also set up a special hotline for people to report in what they know and several suspects have been arrested.
"The judgement of the school and pupils is based solely on the exams, I think anyone can take advantage of that," continues Mandy. "It is criminal really, and once they have caught them they should be treated as criminals."