firefox unable to open signalcaptcha://signal-hcaptcha.... links

[UltimateSolar]

Using a supported version?

• I have searched searched open and closed issues for duplicates.
• I am using Signal-Desktop as provided by the Signal team, not a 3rd-party package.

Overall summary

Hi

thanks for signal and privacy (also thanks for not using Google captchas)

hCaptcha is a service of Intuition Machines, Inc. ("IMI"), a Delaware US Corporation (#6393793).
Mailed inquiries may be sent to: Intuition Machines, Inc., 350 Alabama St, San Francisco, CA 94110.

whois 104.19.229.21; # hosted at cloudflare.com
https://www.investing.com/equities/cloudflare-inc-ownership

once again the browser intergration of all this electron js pseudo programs ain't workin :( (this not only happens with signal but also with slack)

tested on:

• Firefox version 135.0.1 (64-bit); # latest at 2025-02-19
  hostnamectl
• Operating System: Debian GNU/Linux trixie/sid
  Kernel: Linux 6.11.5-amd64
  Architecture: x86-64
• MATE Desktop

it is basically impossible to make firefox tell what to do with signalcaptcha://signal-hcaptcha.jskdlfjdklfj-ajksdjfklajsdkf-aksdfjkldjfkl.challenge.P1_jaskdjfkldjkfljskdlfjkdlsjfkldjf

it usually forwards it to the default search engine which then says (which is probably a privacy catastrophe?)

or it says "string too long"

how to fix this?

read all of this and nothing is working #6455

no appending sgnl:// also does not work

maybe have a chat with those folks at Mozilla WHAT THE F*** IS GOING ON? X-D

Steps to reproduce

1. install signal on GNU Linux Debian
2. send same message to at least 3 people
3. solve captcha
4. try to click "Open Signal" link (it ain't workin)

Expected result

should open signal and verify the user is no bot

Actual result

nothing happens

Screenshots

No response

Signal version

Signal Desktop 7.39.0 ⁨production⁩

same for

Signal Desktop 7.41.0 ⁨production⁩

btw

Operating system

Debian 13

Version of Signal on your phone

No response

Link to debug log

No response

PS: so if it's basically a website (js and all) inside some fancy desktop frame... just do it like slack

and have a 100% web based client at https://signal.org/webclient

currently also not using the native (snap) slack client because of exactly this communication problem between some electron js pseudo desktop program and the default browser

[UltimateSolar]

btw https://www.bleepingcomputer.com/news/security/russian-phishing-campaigns-exploit-signals-device-linking-feature/

[jamiebuilds-signal]

signalcaptcha:// is a custom protocol handler that we set up with the operating system in order to launch the Signal Desktop app instead of your browser.

Are you manually pasting this link into your browser?

[UltimateSolar]

trying both click on link and pasting same problem

[UltimateSolar]

or do it differently: the verification link should be a normal link (https://) that tells the server "clientID xyz is now authorized" and the client is getting that from the server... not from firefox?