I've never seen a Kernel Panic report with that failure before, but my guess it will be a memory or Logic Board issue ("has extra bits....corrupted?"). It is very hard to figure out which it is because they are so closely linked, but a memory failure is usually more likely. You can hope it is bad memory as it is cheaper and easier to fix. Plus one Kernel Panic report is not usually enough since it is best to compare multiple Kernel Panic reports to see if there are any patterns to the failure.
You can try running the Apple Diagnostics to see if any hardware issues are detected. The only useful diagnostic is one which produces an error result or freezes the computer while running the test.
You can try a longer more thorough memory test by using Memtest86. You may need to modify the computer's security settings to allow booting from USB by using the Startup Security Utility. While you should run Memtest86 at the default settings, I would also suggest modifying Memtest86's CPU settings to "Sequential" and also "Round Robin" as these two options sometimes will be more likely to discover a problem. Sometimes Memtest86 will freeze while running the tests....this is good because then you can remove a single memory module and run the tests again to see if it happens again. An actual error message or a frozen test are both useful in trying to figure out which memory module may be bad (or even which memory slot). However, just because the tests pass and don't freeze up, it does not necessarily mean the issue is resolved. Of course the more repeatable the failure, then the more likely you have discovered/fixed the problem if running the tests multiple times does not encounter an error or problem.
Make sure to unplug the iMac when removing or inserting memory, otherwise you may damage the memory and/or the Logic Board. Best to wait a little bit after unplugging the computer before removing or inserting memory as well. I like to press the power button for a few seconds to help drain electricity from the circuits.
If you need to purchase memory, then it is best to only purchase memory from Crucial or OWC for best compatibility. Make sure to use the tools on their respective websites in order to identify the exact part numbers compatible with your exact model Mac. If you purchase Crucial or OWC memory from a third party reseller, then make sure the part numbers indicated by the Crucial or OWC matches what the third party reseller has listed. For Crucial memory, the vendor should have "Mac Compatible" or "For Mac" listed in the product description and it should also be listed on the plastic packaging when you receive the Crucial memory.
