Open Bug 1935968 Opened 2 months ago Updated 3 days ago

cfspart-idp.impots.gouv.fr -A "Firefox is not supported" banner is triggered when accessing the page

Categories

(Web Compatibility :: Site Reports, defect, P2)

ARM
Android

Tracking

(Webcompat Priority:P2, Webcompat Score:6, firefox133 affected, firefox134 affected, firefox135 affected)

ASSIGNED
Webcompat Priority P2
Webcompat Score 6
Tracking Status
firefox133 --- affected
firefox134 --- affected
firefox135 --- affected

People

(Reporter: rbucata, Assigned: twisniewski)

References

(Depends on 1 open bug, )

Details

(Keywords: webcompat:needs-contact, webcompat:site-report, webcompat:sitepatch-applied, Whiteboard: [webcompat-source:web-bugs][webcompat:sightline])

User Story

platform:windows,mac,linux,android
impact:unsupported-warning
configuration:general
affects:all
branch:release
diagnosis-team:webcompat
user-impact-score:400

Attachments

(2 files)

Environment:
Operating system: Android 14
Firefox version: Firefox Mobile 133.0

Steps to reproduce:

  1. Navigate to: https://cfspart-idp.impots.gouv.fr/oauth2/authorize?authType=sso&scope=openid+profile+authChoice+otpEscape&redirect_uri=https%3A%2F%2Fcfspart.impots.gouv.fr%2F%3Fopenidconnectcallback%3D1&display=&state=8ae498d569100eb1bb914c4f0dadf53f9e13e8f469a15520c7e853d4512e8e80&prompt=login&client_id=52ed02940b0f1c57512f2d6fd064dddffccdea03&nonce=xwljDetpOI8D8kuji5Y4mg&response_type=code
  2. Observe the page header

Expected Behavior:
No warning messages are displayed

Actual Behavior:
Unsupported browser banner is triggered

Notes:

  • Reproduces regardless of the status of ETP
  • Reproduces in firefox-nightly, and firefox-release
  • Does not reproduce in chrome

Created from https://github.com/webcompat/web-bugs/issues/144997

Attached image ff vs chrome

Since nightly and release are affected, beta will likely be affected too.
For more information, please visit BugBot documentation.

Whiteboard: [webcompat-source:web-bugs] → [webcompat-source:web-bugs][webcompat:sightline]
Severity: -- → S3
User Story: (updated)
Priority: -- → P2
User Story: (updated)

I can reproduce this on Desktop in Responsive Design Mode, and I can confirm it's just UA sniffing, specifically in:
https://cfspart-idp.impots.gouv.fr/static/part/js/nav.js

The function "guess" there uses navigator.userAgent to get your browser and version, and then cat() uses the result of that to check whether your browser version is beyond the minimum supported one.

They have their minimum-supported-version per browser here: https://cfspart-idp.impots.gouv.fr/static/part/js/matrix.js
which has "firefox":102 but "firefox for android":0 (where 0 means no version is acceptable).

Anyway - UA spoofing as Chrome does successfully get us past this, so we could just ship a ua-spoofing intervention here.

Webcompat Priority: --- → P3
Keywords: leave-open
Assignee: nobody → twisniewski
Status: NEW → ASSIGNED
Pushed by twisniewski@mozilla.com: https://hg.mozilla.org/integration/autoland/rev/0e7156387ee5 add an Android only UA override for cfspart-idp.impots.gouv.fr; r=denschub,webcompat-reviewers
User Story: (updated)
Webcompat Priority: P3 → P2
Webcompat Score: --- → 6
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