Bug 508505

Summary:	Lockscreen only accepts first enrolled fingerprint
Product:	[Plasma] plasmashell	Reporter:	sidpranjale127
Component:	Screen locking	Assignee:	Plasma Bugs List <plasma-bugs-null>
Status:	REPORTED ---
Severity:	normal	CC:	kdedev, nate
Priority:	NOR
Version First Reported In:	6.4.4
Target Milestone:	1.0
Platform:	CachyOS
OS:	Linux
Latest Commit:		Version Fixed/Implemented In:
Sentry Crash Report:

Description sidpranjale127 2025-08-20 08:15:06 UTC

SUMMARY
kscreenlocker only accepts the first fingerprint registered on the system, if you have multiple registered. I have right index and right thumb enrolled, in that order, and right thumb works for sudo or polkit, but kscreenlocker only unlocks with right index and spits out "failed to match fingerprint" on right thumb.

STEPS TO REPRODUCE
1. Enroll multiple fingerprints. (right index and right thumb, for example)
2. Lock your screen
3. Attempt to unlock with any fingerprint that wasn't the first to be enrolled

OBSERVED RESULT
"Failed to match fingerprint"

EXPECTED RESULT
The computer unlocks

SOFTWARE/OS VERSIONS
Operating System: CachyOS
KDE Plasma Version: 6.4.4
KDE Frameworks Version: 6.17.0
Qt Version: 6.9.1
Kernel Version: 6.16.1-1-cachyos-bore (64-bit)
Graphics Platform: Wayland
Processors: 12 × AMD Ryzen 5 7600 6-Core Processor
Memory: 32 GiB of RAM (30.9 GiB usable)
Graphics Processor: NVIDIA GeForce RTX 3070
Manufacturer: ASRock
Product Name: B650M-HDV/M.2

Comment 1 TraceyC 2025-08-20 17:01:51 UTC

I'm not able to reproduce this on Plasma built from git-master. I have two fingerprints enrolled, and both allow me to unlock my session.
It's clearly not a hardware or driver issue, since both your enrolled fingerprints work in situations other than the lock screen.

I'll leave this open to see if anyone else can reproduce.