Story highlights Committee says it does not rule out the possibility an attack caused a Brexit voter registration website to crash

"There is no evidence to suggest malign intervention," the UK Cabinet Office says

London (CNN) Foreign hacking could have occurred during last year's Brexit referendum but didn't make any difference to the outcome, according to a report published Wednesday by a UK parliamentary committee.

Prior to the UK's referendum on leaving the European Union last June, the website for voter registration crashed . The UK government extended the June 7 deadline for voters to register to vote by a day as a result.

In a report on the lessons to be learned from the EU referendum, the Public Administration and Constitutional Affairs Committee said it "does not rule out the possibility that the crash may have been caused by a DDOS (distributed denial of service attack) using botnets."

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Its authors add that they "do not believe that any such interference had any material effect on the outcome of the EU referendum" but say they are "deeply concerned about these allegations about foreign interference."

The Cabinet Office on Wednesday firmly denied that any foreign hacking caused the website to crash.

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