TOPIC: CHATGPT ATLAS
Comet and Atlas: Navigating the security risks of AI Browsers
2nd November 2025The arrival of the ChatGPT Atlas browser from OpenAI on 21st October has lured me into some probing of its possibilities. While Perplexity may have launched its Comet browser first on 9th July, their tendency to put news under our noses in other places had turned me off them. It helps that the former is offered extra charge for ChatGPT users, while the latter comes with a free tier and an optional Plus subscription plan. My having a Mac means that I do not need to await Windows and mobile versions of Atlas, either.
Both aim to interpret pages, condense information and carry out small jobs that cut down the number of clicks. Atlas does so with a sidebar that can read multiple documents at once and an Agent Mode that can execute tasks in a semi-autonomous way, while Comet leans into shortcut commands that trigger compact workflows. However, both browsers are beset by security issues that give enough cause for concern that added wariness is in order.
In many ways, they appear to be solutions looking for problems to address. In Atlas, I found the Agent mode needed added guidance when checking the content of a personal website for gaps. Jobs can become too big for it, so they need everything broken down. Add in the security concerns mentioned below, and enthusiasm for seeing what they can do gets blunted. When you see Atlas adding threads to your main ChatGPT roster, that gives you a hint as to what is involved.
The Security Landscape
Both Comet and Atlas are susceptible to indirect prompt injection, where pages contain hidden instructions that the model follows without user awareness, and AI sidebar spoofing, where malicious sites create convincing copies of AI sidebars to direct users into compromising actions. Furthermore, demonstrations have included scenarios where attackers steal cryptocurrency and gain access to Gmail and Google Drive.
For instance, Brave's security team has described indirect prompt injection as a systemic challenge affecting the whole class of AI-augmented browsers. Similarly, Perplexity's security group has stated that the phenomenon demands rethinking security from the ground up. In a test involving 103 phishing attacks, Microsoft Edge blocked 53 percent and Google Chrome 47 percent, yet Comet blocked 7 percent and Atlas 5.8 percent.
Memory presents an additional attack surface because these tools retain information between sessions, and researchers have demonstrated that memory can be poisoned by carefully crafted content, with the taint persisting across sessions and devices if synchronisation is enabled. Shadow IT adoption has begun: within nine days of launch, 27.7 percent of enterprises had at least one Atlas download, with uptake in technology at 67 percent, pharmaceuticals at 50 percent and finance at 40 percent.
Mitigating the Risks
Sensibly, security practitioners recommend separating ordinary browsing from agentic browsing. Here, it helps that AI browsers are cut down items anyway, at least based on my experience of Atlas. Figuring out what you can do with them using public information in a read-only manner will be enough at this point. In any event, it is essential to keep them away from banking, health, personal accounts, credentials, payments and regulated data until security improves.
As one precaution, maintaining separate AI accounts could act as a boundary to contain potential compromises, though this does not address the underlying issue that prompt injection manipulates the agent's decision-making processes. With Atlas, disable Browser Memories and per-site visibility by default, with explicit opt-ins only on specific public sites. Additionally, use Agent Mode only when not logged into any accounts. Furthermore, do not import passwords or payment methods. With Comet, use narrowly scoped shortcuts that operate on public information and avoid workflows involving sign-ins, credentials or payments.
Small businesses can run limited pilots in non-sensitive areas with strict allow and deny lists, then reassess by mid-2026 as security hardens, while large enterprises should adopt a block-and-monitor stance while developing governance frameworks that anticipate safer releases in 2026 and 2027. In parallel, security teams should watch for circumvention attempts and prepare policies that separate public research from sensitive work, mandate safe defaults and prohibit connections to confidential systems. Finally, training is necessary because users need to understand the specific risks these browsers present.
How Competition Might Help
Established browser vendors are adding AI capabilities on top of existing security infrastructure. Chrome is integrating Gemini, and Edge is incorporating Copilot more tightly into the workflow. Meanwhile, Brave continues with a privacy-first stance through Leo, while Opera's Aria, Arc with Dia and SigmaOS reflect different approaches. Current projections suggest that major browsers will introduce safer AI features in the final quarter of 2025, that the first enterprise-ready capabilities will arrive in the first half of 2026 and that by 2027 AI-assisted browsing will be standard and broadly secure.
Competition from Chrome and Edge will drive AI assistance into more established security frameworks, while standalone AI browsers will work to address their security gaps. Mitigations for prompt injection and sidebar spoofing will likely involve layered approaches combining detection, containment and improved user interface signals. Until then, Comet and Atlas can provide productivity benefits in public-facing work and research, but their security posture is not suitable for sensitive tasks. Use the tools where the risk is acceptable, keep sensitive work in conventional browsers, and anticipate that safer versions will become standard over the next two years.