We cover browser market share data on an occasional basis, with the lack of a regular schedule being due to the fact that it"s fairly unchanged month to month, as Chrome continues to crush the competition. However, just because something is popular doesn"t necessarily mean that it is also the best, and this is exactly what a new report that evaluates browsers on user privacy emphasizes.
According to a December 2025 study conducted by Digitain on risks to user privacy, ChatGPT Atlas is the worst browser in this area. This shouldn"t be particularly surprising considering that the browser created by OpenAI is very new, but it is concerning that it apparently isn"t built with privacy in mind at all. ChatGPT Atlas failed all state partitioning tests, which means that it does not actively block websites from tracking users across different sessions. The browser ranked quite low across all three evaluated metrics (privacy and anti-fingerprinting, tracker and data blocking, connection and navigation security), giving it an overall privacy risk score of 99 out of 100.
The world"s most popular browser, Google Chrome, came in as the second worst browser. However, it was only slightly better than ChatGPT Atlas in the three aforementioned areas, netting it a score of 76 out of 100. Vivaldi scored roughly the same at 75, while Edge was next at 63, which is also quite high risk. Here is the list of the top 10 worst browsers when it comes to user security, along with their risk scores (the lower, the better in terms of privacy):
- ChatGPT Atlas - 99
- Google Chrome -76
- Vivaldi - 75
- Microsoft Edge - 63
- Opera - 58
- Ungoogled - 55
- Mozilla Firefox - 50
- Apple Safari - 49
- DuckDuckGo - 44
- Tor - 40
Paruyr Harutyunyan, Group head of Digital Marketing at Digitain, further noted that:
"New AI-powered browsers like ChatGPT Atlas and Comet from Perplexity are getting a lot of attention right now, and millions of people are trying them out because of the AI hype. These browsers come with interesting features that traditional ones don"t have, but users need to stop and check how secure they actually are. AI works by collecting and learning from data, which means these tools might be gathering more of your personal information than you realize. Just because something uses AI doesn"t automatically make it safe or private."
Interestingly, Brave and Mullvad Browser were touted as the browsers with the most focus on user privacy. Although the former is a fairly known option for many, the latter is a result of a collaboration between Mullvad VPN and The Tor Project. It is marketed as an open-source privacy-focused browser that minimizes tracking.