Big Sur Safari Not Displaying Correct Version

Since upgrading to Mac OS Big Sur, Duo presents an error when authenticating via Safari. I am running 11.2.1 and the authentication window displays that I am running 10.15.6. Is there a fix for this so that I can authenticate via Safari?

Chrome does not experience the same issue and works fine for web based apps, however desktop applications such as Office only launch the authentication window in Safari so I can no longer use them until this is resolved.

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Hi there, sorry to hear you are experiencing this issue! Duo uses the browser user agent to determine the OS version, and unfortunately in Apple’s latest update, the user agent is reporting incorrectly from the Safari browser. Please see this article on how Duo determines device information such as OS for more info.

If you are a Duo admin, what you can do is make allowances in your policy to allow for the incorrect version the Safari user agent string is reporting. You are also welcome to reach out to Apple to ensure Safari is reporting the correct OS version for the OS on which it is installed on rather than 10.15.6. You should also let Apple know of the issue, as this is something they have to fix on their end.
If you’re not a Duo admin, you should contact your IT help desk and report this to them, so they can notify the administrator and have them take the proper steps. I hope that helps!

For some context, the incorrect user agent reporting is a known (and relatively deliberate) problem with WebKit, the open source web browser engine that underpins Safari:

https://bugs.webkit.org/show_bug.cgi?id=216593

Depending on the User Agent is problematic. And there is no good resolution for this particular problem.