The privately held company said it had fixed a loophole in its cloud messaging system that had triggered the unauthorised data transfer and that the operating system upgrade had been rolled out on Sunday.
The issue was highlighted last week in a blog post by security firm F-Secure Oyg and had been reported by media outlets in Taiwan. Like Apple Inc's iMessage service, Xiaomi lets users avoid SMS charges by routing messages over the internet rather than through a carrier's network.
In a lengthy blogpost on Google Plus, Xiaomi Vice-President Hugo Barra apologised for the unauthorised data collection and said the company only collects phone numbers in users' address books to see if the users are online.
He said the smartphone's messaging system would now only activate on an "opt-in" basis and that any phone numbers sent back to Xiaomi servers would be encrypted and not stored.
Some industry analysts say Xiaomi has pipped Samsung Electronics Co Ltd to become the top selling smartphone brand in China, the world's biggest smartphone market.
Although an increasing number of smartphone apps harvest vast troves of personal data including a user's real-time location, the address book remains a particularly sensitive domain. The US Federal Trade Commission fined the social network Path $800,000 last year after security researchers showed how the company siphoned users' address books without their knowledge and stored it on its servers.
As a result of the Path controversy, which began in 2012 and prompted a brief Congressional inquiry, Apple changed its iPhone operating system so that app developers would have to ask explicitly for permission before accessing address book data.
You’ve reached your limit of {{free_limit}} free articles this month.
Subscribe now for unlimited access.
Already subscribed? Log in
Subscribe to read the full story →
Smart Quarterly
₹900
3 Months
₹300/Month
Smart Essential
₹2,700
1 Year
₹225/Month
Super Saver
₹3,900
2 Years
₹162/Month
Renews automatically, cancel anytime
Here’s what’s included in our digital subscription plans
Exclusive premium stories online
Over 30 premium stories daily, handpicked by our editors


Complimentary Access to The New York Times
News, Games, Cooking, Audio, Wirecutter & The Athletic
Business Standard Epaper
Digital replica of our daily newspaper — with options to read, save, and share


Curated Newsletters
Insights on markets, finance, politics, tech, and more delivered to your inbox
Market Analysis & Investment Insights
In-depth market analysis & insights with access to The Smart Investor


Archives
Repository of articles and publications dating back to 1997
Ad-free Reading
Uninterrupted reading experience with no advertisements


Seamless Access Across All Devices
Access Business Standard across devices — mobile, tablet, or PC, via web or app
)