[plingbang]

I remember MS Teams opening various files within itself instead of launching an appropriate program. I wonder what they're using for rendering PDFs.

[gostsamo]

At least edge uses a module from word as far as I know and I'd expect the same for teams. They likely are not affected.

[Gare]

That's why I use MS Teams (on desktop) via browser only. Keeps it nicely sandboxed.

[yencabulator]

And if they had used PDF.js incorrectly in the browser, it would allow XSS attacks on the domain used for MS Teams.