The personal data of more than 106 million travellers to Thailand were exposed online.
A UK cybersecurity research firm spotted the unencrypted data online but there is no evidence any data was stolen.
"Any foreigner who travelled to Thailand in the last decade might have had their information exposed in the incident," said Bob Diachenko, head of cybersecurity research at Comparitech.
The unprotected database contained information of travellers dating back to 2011.
The cybersecurity gap was plugged by Thai authorities a day after been informed of it last month.
"However we do not know how long the data was exposed prior to being indexed," Comparitech said in a report.
It didn’t disclose what traveller personal data was visible, or if it contained any sensitive financial information.
