Password Typed During Lock Screen Wake-Up Appears in Foreground App After Login

Distribution

Mint 22.1

Package version

Cinnamon 6.4.8

Graphics hardware in use

NVidia GeForce 3090 - 3 monitors (staggered wake times observed)

Frequency

Only occasionally

Bug description

While unlocking the system, if the user begins typing their password before all monitors have fully woken and the lock screen is visibly ready, some or all of the keystrokes typed may be passed through to the underlying application rather than being captured exclusively by the lock screen. This results in parts of the password unexpectedly appearing in input fields of the previously active application (e.g., browser, text editor, or terminal) after a successful login.

It is unclear whether the lock screen receives the full password attempt, or if the input is entirely passed through during this state.

Steps to reproduce

1. Lock the screen with at least one application open that accepts text input (e.g., a text editor, web browser input field, terminal).
2. Let the monitors go to sleep or wait for the lock screen to activate fully.
3. Begin typing the password before the monitors or lock screen fully wake up.
4. After logging in successfully, check the previously focused application window.

Expected behavior

All keystrokes typed before the lock screen is fully visible and focused should be discarded or captured by the lock screen only.

Additional information

Some or all characters typed are passed through to the previously active application and appear in its input field after login.

No file, test, or entry point is named in the report. Start by reproducing the wake-up timing with multiple monitors and an application accepting text, then trace Cinnamon's lock-screen activation and input handling; done means early keystrokes are not delivered to the previously focused application.