According to a recent report making its rounds on the internet, the in-display fingerprint sensor in the Galaxy S10 doesn't offer much in the way of security if you are using the wrong accessories. For one UK couple using an inexpensive "gel" screen protector (or case, it isn't immediately clear which), their cheap accessory compromised the phone's fingerprint recognition capabilities by allowing any finger to unlock the phone, eliminating the security offered by the in-display reader.

For a bit of context, there are two types of in-display fingerprint readers out there: optical and ultrasonic. Some companies have championed that the ultrasonic varieties are more secure than the optical versions, which are supposed to be slightly easier to fool. The Galaxy S10's solution is an ultrasonic system made by Qualcomm.

This was first reported by The Sun, and there are a few incongruities in the original story like an apparent confusion between the highly technical terms "screen protector," "cover," and "case," but the gist seems to be that a couple purchased a cheap accessory from eBay, and the proper operation of the in-display fingerprint sensor ceased while it was being used, allowing any fingerprint access to the phone.

There are some lingering questions, like if the fingerprints were re-registered after applying the accessory — claimed at times to be a screen protector and at others to be a case — or if the incongruities in the original story indicate some type of accessory misuse. Some have speculated that an "air gap" in the cheap accessory may be to blame, giving the sensor identical data through the screen protector/cover/case/whatever regardless of the finger applied. For our part, we've tried to reproduce the effect on our own Galaxy S10 models here at Android Police with cheap sources of flexible transparent plastic at hand, and we haven't been able to succeed.

We reached out to Samsung for comment and were provided the following statement:

"We are investigating this issue and will be deploying a software patch soon. We encourage any customers with questions or who need support downloading the latest software to contact us directly at 1-800-SAMSUNG.”

In the meantime, consider sticking to higher-quality screen protectors and cases on your Galaxy S10 until this is sorted, and take off that cheap eBay special you're using now.

This video on Twitter, showing the ultrasonic fingerprint sensor on a Galaxy Note10 failing when used through a flexible TPU case, could be showing off the same issue:

Hopefully, more details surrounding precisely why this is occurring will surface. Previously, optical readers were rumored to fall for something like this, where existing fingerprints/finger oil on the surface of the display could be re-used to unlock the device with the right materials. It was assumed that the ultrasonic sensors manufactured by Qualcomm were immune, and we aren't sure if this is demonstrating some variation of that same exploit or an entirely new issue.

Samsung has released a much longer statement through its newsroom regarding this issue, which the company describes as "fingerprint sensors unlocking devices after recognizing 3-dimensional patterns appearing on certain silicone screen protecting cases as users’ fingerprints."

In the meantime, Galaxy S10-series and Note10-series customers using "front screen protective covers" are advised to remove them, delete existing fingerprint data, and re-register your fingerprints more cleanly as we wait for an update to fix the issue, which could be here next week. To our eye, this phrasing sounds like Samsung is telling everyone using a screen protector to remove it. We reached out for clarification, in case that interpretation was in error, but none was forthcoming at the time of publication.

Samsung's full statement is just below:

"Regarding recent reports of a fingerprint recognition issue affecting certain Galaxy devices, we would like to inform our customers of the following information.

This issue involved ultrasonic fingerprint sensors unlocking devices after recognizing 3-dimensional patterns appearing on certain silicone screen protecting cases as users’ fingerprints.

To prevent any further issues, we advise that Galaxy Note10/10+ and S10/S10+/S10 5G users who use such covers to remove the cover, delete all previous fingerprints and newly register their fingerprints.

If you currently use front screen protective covers, to ensure optimum fingerprint scanning, please refrain from using this cover until your device has been updated with a new software patch.

A software update is planned to be released as early as next week, and once updated, please be sure to scan your fingerprint in its entirety, so that the all portions of your fingerprint, including the center and corners have been fully scanned.

Thank you for your patience and we will strive to continuously improve product and service experiences for our users."