1852427 - "Request Header Fields Too Large" in captive portal (https://wifi.bahn.de/cna/)

Status: RESOLVED INCOMPLETE

(Core :: Networking, defect)

Description

[Karl]

User Agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:109.0) Gecko/20100101 Firefox/116.0

Steps to reproduce:

come online in a Wifi network with captive portal (here: https://wifi.bahn.de/cna/ )

Actual results:

the page shows "Request Header Fields Too Large" instead of the fancy acknowledgement page.
This issue is intermittent, sometimes it works fine, sometimes this happens. Meanwhile I discovered that when the issue occurs in a normal browsing window, it still works (captive portal page appears) in a private browsing window.
Looking at Ctrl-I "General" shows very little info but in "Security" it says: "Is this website storing information on my computer? Yes, cookies and 184KB of site data" so this might explain what could be put in the request header.
Please advise what more information I can gather next time it happens to help diagnose the issue. Thank you.

Expected results:

see above

Comment 1

[BugBot [:suhaib / :marco/ :calixte]]

The Bugbug bot thinks this bug should belong to the 'Core::Networking' component, and is moving the bug to that component. Please correct in case you think the bot is wrong.

Comment 2

[Kershaw Chang [:kershaw]]

Hi Karl,

If you can reproduce this reliably, could you try to record a http log? If possible, we'd like to see the content of Set-Cookie header from the server and the Cookie header sent from Firefox.

Thanks.

Comment 3

[Randell Jesup [:jesup] (needinfo me)]

Resolving as incomplete for now, but please re-open or re-file if you can still reproduce this problem