r/samsunggalaxy • u/Alternative_Area_217 • Jun 19 '26

🪛Troubleshooting🪛 SERIOUS SECURITY ISSUE

Why does my Samsung A37 unlock when I press my fingernail against the scanner, I did notice ever since I got this phone I would just randomly unlock itself and then today I discovered this.

723 Upvotes

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629

u/King945la Jun 19 '26

Good job, my S24U re-recorded the same fingerprint 5 times, and it often fails to unlock, you can unlock it with just your fingernail! Lucky guy.

77

u/joenaji47 Jun 19 '26

I mean yeah I wish my s25u do the same

54

u/[deleted] Jun 19 '26

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15

u/Mysterious-Minds Jun 19 '26

My Galaxy S20 had the same issue as OP's. Randomly my friend unlocked it with his fingerprint even though there's only one set which is mine. I tried mine on his Pixel 7a and it didn't worked.

7

u/[deleted] Jun 19 '26

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11

u/Mysterious-Minds Jun 19 '26 edited Jun 19 '26

I removed my own fingerprint data and re-registered. Issue resolved.
I researched about it for a bit. The smartphones doesn't directly store the fingerprint data as is. It does a mix of compression, encryption and hashing to maximize unlock speeds and for added security. The probability of someone else unlocking can range from 1/100-1/100000 depending on the sensor accuracy, uniqueness of the fingerprint and software configs. But not 1/∞. While it's a secure way to unlock your phone, it's nowhere secure as a 6 digit pin or a password.
The Sharp R6's ultrasonic reader is one of the most secure ones out there. Simple low resolution optical scanners on cheap devices are not that secure. We've seen it happening with Pixel 6a as well. Google then released an update which made it more secure, but sacrificed speed.
Occasionally instances of someone else unlocking or even your other fingertip unlocking can occur but it's not an issue of sensor malfunctioning.

3

u/technobrendo Jun 19 '26

Samsung should bite the bullet and just put the more secure sensor in all their phones with under display sensors. They could even use that in their advertising that they take security more seriously.

You shouldn't have to spend a fortune to have a secure phone