A bug on the Samsung Galaxy S10 and S10+ allows any fingerprint—not just the owner’s—to activate the phones’ fingerprint unlock feature, if the handset has a screen protector over the display. Samsung acknowledged the flaw and said it is working on a software update to fix the issue. Fortune reached out to Samsung for comments and details but did not receive an immediate response.

Samsung Galaxy S10 and S10+ owners who use screen protectors can protect their phones’ data by turning off the fingerprint ID setting and unlocking their phones using other security features like a passcode or facial recognition until Samsung’s update comes.

Samsung touted the Samsung Galaxy S10’s fingerprint technology as highly advanced, using ultrasound technology fused into the screen that detect the ridges of a fingerprint. Reports also suggest that some screen protectors may leave an air gap that interferes with the technology, as noted by BBC. The Samsung Galaxy Note 10 has similar in-screen fingerprint detection, though it’s unclear whether the S10’s flaw affects that phone as well.

The issue was discovered by accident when a British woman applied a screen protector she purchased cheaply on eBay to Galaxy phone, the Sun initially reported. It allowed her to unlock her phone with fingers she hadn’t previously registered. Her husband’s fingerprint was also able to open it. The same problem appeared on another Galaxy phone as well when the same woman tried it on a relative’s device.

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