The tech giant has promised a software patch to fix the problem after the issue was spotted by a woman whose husband unlocked her handset with his thumbprint simply by using a cheap screen protector.
The company said it was "aware of the case of S10's malfunctioning fingerprint recognition and will soon issue a software patch".
The scanner recognises users by using ultrasounds to detect 3D ridges of fingerprints.
When the S10 launched back in March, Samsung hailed its fingerprint authentication system as "revolutionary".
Previous reports have suggested certain screen protectors are incompatible with the device's reader due to a small air gap which interfered with the scanning.
Meanwhile, in the fallout of the security flaw, the online-only South Korean KaKao Bank has urged its customers to disabled the fingerprint recognition option - which can be used to log on to its services - until Samsung has announced a solution.