Facepalm: Customers of Ethiopia's largest bank had a nice surprise this week when a glitch allowed them to withdraw unlimited funds. More than $40 million was withdrawn from the state-owned Commercial Bank of Ethiopia (CBE) or transferred to other banks, and recouping it isn't going to be easy.

According to local media, CBE didn't initially notice the technical issue that allowed customers to withdraw more money than they had in their accounts. By the time the bank realized what was going on and froze transactions a few hours later, more than 2.4 billion Ethiopian birr (around $40 million) had been withdrawn or moved to other banks.

Bank president Abe Sano told journalists that much of the money had been withdrawn by students. News that the CBE was giving away unlimited money spread across universities in the country via social media, messaging apps and phone calls, writes the BBC. It led to long lines at campus ATMs that lasted until the police arrived to stop people.

A student at Jimma University Institute of Technology said he did not believe his friends when they told him at around 1 am local time that it was possible to withdraw large amounts of money from ATMs or transfer it via the bank app. Another student, at Dilla University, said several people on campus retrieved money from CBE between midnight and 2 am.

Sano stressed that the incident was not a cyberattack. The bank said the glitch was the result of routine "maintenance and inspection activities," and that customer accounts were not affected.

At least three universities have advised students to return any money not belonging to them that they may have taken from CBE. Sano said those returning the money would not be charged with a criminal offense.

It's unclear how much the bank has managed to recoup. An official at Dilla University said bank employees were on campus collecting money that some students were returning voluntarily.

More than 38 million people hold accounts at CBE. The bank says its ATM services are now fully operational, though it may want to rethink its slogan: "The bank you can always rely on!"

Image credit: Karolina Grabowska