[Bug]: WebAuthn authentication failure

[LennyLizowzskiy]

Pre-Submission Checklist

• [X] I have checked the existing/closed issues to ensure this issue has not already been reported.
• [X] I am using the latest supported version of the browser.
• [X] I have tried disabling all browser extensions/add-ons to rule out interference from these.
• [X] I have tried clearing the browser cache and cookies.
• [X] I have tried to create a new profile and the issue still occurs.
• [X] I have provided detailed step-by-step instructions on how to reproduce the issue.
• [X] I have included relevant screenshots or console outputs.
• [X] I have checked this problem is not ocurring in the latest version of Firefox ESR.
• [X] This issue is specific to this browser and does not occur in other browsers.

Bug Summary

Can't login via security key using WebAuthn

Reproduction Steps

1. Try to log into Google using security key
2. See this

Expected Behavior

Browser should prompt me to enter the password to unlock my security key. Screenshot from Firefox ESR 115.11.0:

Actual Behavior

Website shows that some error occured. Issue persists across all websites that use WebAuthn (so GitHub is also affected)

Screenshots

Console output:

Extension error: TypeError: URL constructor:  is not a valid URL. moz-extension://968fc52e-c1bc-4b46-8610-7c8d61f4253c/background.bundle.js 1
[[Exception stack
@moz-extension://968fc52e-c1bc-4b46-8610-7c8d61f4253c/background.bundle.js:1:12331
Current stack
applySafeWithoutClone@resource://gre/modules/ExtensionCommon.sys.mjs:693:41
fire@resource://gre/modules/ExtensionChild.sys.mjs:836:37
recvRunListener@resource://gre/modules/ExtensionChild.sys.mjs:840:13
_recv@resource://gre/modules/ConduitsChild.sys.mjs:77:20
receiveMessage@resource://gre/modules/ConduitsChild.sys.mjs:189:20
]]
JavaScript error: undefined, line 0: Error: Missing host permission for the tab

Browser Version

11.13.2

Operating System

Linux, NixOS 24.05-pre

Additional Context

Webauthn-related Floorp about:config:

[LennyLizowzskiy]

I checked the build scripts for Floorp in Nix repo and it seems like the issue is there, not in the browser itself