Citizen Lab said the Chinese and English language versions of the Browser, developed by UCWeb Inc., made readily accessible to third parties personally identifiable information like place, search details and cellular subscriber and device numbers.

The transmission of the advice “represents a privacy threat for users since it enables anyone with access to the data traffic to recognize users as well as their apparatus, and roll up their private search data”, it said in a report.

Citizen Lab, based in the University of Toronto, said UC Browser was the most famous web browser in India and China and had more than 500 million registered users.

Citizen Lab said the Chinese variant more vulnerable and said that by simply installing and opening those variation users shown “a substantial amount” of private identifiers and location information to third parties.

“By leaking a big volume of fine grained data points to multiple network operators, the UC Browser program is raising the dangers to its users that such data could be utilized against them by authorities, offenders, or other third parties,” it said.

UCWeb was completely got by Alibaba in what was at the time the largest merger in Chinese web history.