This is a summary of our current understanding of the impact of the Chrome SameSite change that has been well-publicized, and has been rolling out in recent Chrome (and now Edge, and other Chromium software) versions in a haphazard fashion. It apparently has hit Firefox beta (https://hacks.mozilla.org/2020/08/changes-to-samesite-cookie-behavior/) but as far as we are aware has never been enabled by Mozilla out of the box to this pointAs of January 2022, Firefox has apparently rolled out the same change.
If you want the gory details, we have a very technical testing summary page at IdP SameSite Testing. This is intended as a more digestible, actionable summary for deployers.
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