1993172 - LastPass extension is freezing Sign into Youtube via google

Status: RESOLVED MOVED

(WebExtensions :: Developer Outreach, defect)

Description

[Konstantina Papadea [:couci]]

A user reported that their Firefox freezes when trying to sign into YT via google.
After investigation looks like it happens because of LastPass.
User is on Firefox 143, Mac OS X 10.15.
Support question: https://support.mozilla.org/en-US/questions/1539886

Comment 1

[grugnog]

Attachment: GMT20251014-000258_Clip_Firefox Lastpass Yubikey freeze.mp4

Reproduction with 2025-9-18 Firefox Nightly build and fresh profile.

Comment 2

[grugnog]

Was able to confirm this - see video above.

Environment

• MacOS Tahoe 26.0.1 (25A362)
• Firefox 143.0.4 (aarch64) and Firefox Nightly 2025-9-18 - both with a fresh profile
• Lastpass Extension 4.146.9
• Yubikey (tested with 4 and 5)

Steps to reproduce:

• Make sure you have a security key second factor on your Google account
• Complete user/pass login as normal

Expected results:

• MacOS passkey window appears
• Touch disc on security key
• Logged in

Actual results:

• MacOS passkey window appears briefly then disappears - or occasionally stays on screen
• Firefox windows immediately freezes - no keyboard or mouse activity has any effect. The OS level menus still work and can be used to exit. If the MacOS passkey window is present it is also frozen.

Notes:

• This occurs on any Google login page, not just YouTube.
• It does seem specific (for me at least) to having a security key second factor/passkey set up on your Google account - Konstantina, can you confirm what second factor your user has setup?
• I also tested setting security.webauthn.enable_macos_passkeys to FALSE, but that did not work.
• This seems to have started sometime in the last 2-3 weeks - I can't tell if it was a MacOS or Firefox change though.

Comment 3

[Luca Greco [:rpl] [:luca] [:lgreco]]

Moving to Developer Outreach to be notified to the LastPass developers, see comment 2 for the STR and precise version of the Lastpass extension.

Comment 4

[grugnog]

This issue also seems likely to be the same thing, although I think there may well be something to fix in the Lastpass extension as well as whatever is causing Firefox to freeze.

Comment 5

[grugnog]

I also noticed that this occurs even when a Yubikey is not present on the device, so I don't think it is anything specific to that, but rather the MacOS Passkey integration itself.

Comment 6

[grugnog]

In the other issue, it was confirmed that downgrading to LastPass to version 4.145.0 fixes the issue.

Comment 7

[grugnog]

I have opened a Lastpass support request to hopefully get there attention - case number 02964149 in case anyone from Lastpass is looking here.

Comment 8

[John Schanck [:jschanck]]

Is this still an issue with LastPass Version 4.147.2?

Comment 9

[grugnog]

Yes, this is still an ongoing issue with LastPass 4.147.2 and 144.0.2 (aarch64). Lastpass is still working on this according to my support ticket.

Comment 10

[Abhishek Nagekar [:Abhi]]

Developer notified via AMO