Im curious if the memory Tagging feature on the pixel 8/9 generation phones could be used to find and prevent exploits in previous generation pixels that don't support memory Tagging.

For instance, if an exploit is discovered on a pixel 8 using the memory Tagging feature, and the exploit is patched on the pixel 8, would that same patch be implemented downstream to a pixel 7 phone? Or at the very least would the exploit being found with the memory Tagging feature at least give an educated hint about possible exploits on previous generation pixels? Thanks.

A memory corruption bug being detected by hardened_malloc or by MTE that is reported to that app's developers to be fixed will impact every Android device if it is indeed fixed.

GrapheneOS' hardened_malloc and the fact that we enable MTE has already resulted in many memory corruption bugs being found in apps, including very widespread and popular ones, and then being fixed because of it. Sometimes it's code in the apps themselves, otherwise it can be in upstream code from even those projects (such as in Flutter code, for example) etc.