Detailed diagrams of the site of a UN summit to be held in Glasgow later this year were accidentally put online.
The COP26 climate conference is being planned for November and as part of the tendering process the UK government uploaded them in error.
The Mail on Sunday highlighted the mistake and described it as an "astonishing security breach".
The UK government said it was continuing to work with Police Scotland to make sure the event was secure.
It was understood the documents, which have since been removed, did not show detailed infrastructure or security layers within and around the buildings. However, they are not typically shared publicly.
The newspaper claims that an unsecured website contained 19 files including plans for "every area of the event space's buildings room by room", including things like sprinkler valve rooms and the power hub.
About 30,000 people, including some 200 world leaders, are expected to attend COP26.
Police Scotland has previously warned that the cost of providing security could be more than £200m - partly because the force will need to bring in officers from elsewhere in the UK to help.
A spokeswoman for the UK government said: "We are continuing to work very closely with Police Scotland and the relevant authorities to ensure COP26 is a secure and welcoming event for all participants."
The Scottish government said it had been made aware of the issue by the UK government but that it was confident the event would be secure and welcoming.
The conference is due to be held at the Scottish Events Campus between 9 and 19 November, but there have been concerns about spiralling costs amid claims that the UK and Scottish governments have been at loggerheads over planning for the event.
What is COP26?
- It's a UN-led annual meeting set up to assess progress on tackling climate change
- COP stands for Conference of the Parties. The parties in question are countries that have ratified the United Nations Framework Convention on Climate Change (UNFCCC)
- The UNFCCC is an international environmental treaty that came into force on 21 March 1994
- The first COP meeting took place in Berlin, Germany, in 1995
- COP26, in November, will see about 200 world leaders meet in Glasgow to agree a new, long-term deal on rising temperatures
- It's seen as particularly important because the Madrid COP last year left a raft of complex issues unresolved