Comcast is adding motion detection to millions of routers, and I’m worried it’s a privacy nightmare

• August 19, 2026

Worried about intruders sneaking around inside your house when you’re out of town? You could get one of the best home security cameras, but what if your existing router could do some of the heavy lifting? That’s what Comcast has just started offering its customers, but the move has been met with considerable controversy.

Dubbed WiFi Motion, the new feature is coming to Comcast-owned Xfinity’s internet services. Once you opt in, WiFi Motion detects changes in the Wi-Fi signals emitted by the company’s routers and other smart home devices to detect the presence of people in your home. While there’s no video surveillance involved, it can be used as a basic way to sense people who should not be inside your house. When that happens, you’ll receive a notification in the Xfinity app.

While Xfinity told The Verge that WiFi Motion would provide “a basic level of security,” it’s caused a degree of consternation among the general public — and not for the first time. On Reddit, for example, one user described it as “Flock for your bedroom,” likening the system to Flock’s controversial numberplate-recognition cameras.

Another worried that “A few years from now they’ll be hit with a few million-dollar fine or lawsuit while profiting hundreds of millions from selling the data.” In a world where user data forms a lucrative trade and data brokers increasingly siphon off people’s private information, it’s unsurprising that users are apprehensive about where their presence data might end up.

“Conspiracy guys were saying for probably a decade that they could use Wi-Fi to fully map out the interior of your house and track you,” added another Redditor. “Crazy that it’s just out in the open now.”

A potential privacy nightmare

The privacy concerns for technology like this are wide-ranging. While many people already have indoor security cameras that can see who is walking around inside their homes, these people have consciously bought these products and opted into the system.

When surveillance is added to a router, though, we’re talking about orders of magnitude more people being affected — potentially many millions, in this instance. Moreover, most of them will not have bought a router for its tracking abilities, yet will find themselves with a device that can do just that. That’s enough to make anyone feel uneasy.

Once a system like this is in place on millions of routers, it opens a massive door to potential misuse — users simply have to trust that Xfinity is using this data responsibly, with no way of knowing if that’s actually the case. Who can see the data? How long is it retained? Are there proper checks in place? We don’t know the answers to any of these questions.

It also paints a huge target on the data. Any time private data is collected en masse, hackers start snooping around. If someone was able to hack into your router and use its presence detection to determine that no one was home, it would be simple to then disable the system and pick the optimal time for a burglary.

Even discounting all of that, there’s another privacy issue: Comcast says that enabling the feature means it might share your Wi-Fi Motion data with third parties at its discretion.

As per an Xfinity support page, “Comcast may disclose information generated by your WiFi Motion to third parties without further notice to you in connection with any law enforcement investigation or proceeding, any dispute to which Comcast is a party, or pursuant to a court order or subpoena.”

We also don’t know if firmware updates will respect a user’s decision not to opt in to Comcast’s router-based presence tracking. For now, the company says that the feature is opt-in, but can we guarantee that that will always be the case? And if a future software update opts people in automatically, can you trust Comcast to explicitly tell you when that happens?

While this new router feature might be well-intentioned, it raises all manner of security and privacy concerns. If you’re worried about the implications for you and your family, replace your Comcast router with one of our picks for the best router money can buy. And if you need to, consider one of the best home security cameras if you still want to be alerted to unwanted intruders.

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Worried about intruders sneaking around inside your house when you’re out of town? You could get one of the best home security cameras, but what if your existing router could do some of the heavy lifting? That’s what Comcast has just started offering its customers, but the move has been…