In the Linux kernel, the following vulnerability has been resolved:
arm64: set UXN on swapper page tables
[ This issue was fixed upstream by accident in c3cee924bd85 ("arm64: head: cover entire kernel image in initial ID map") as part of a large refactoring of the arm64 boot flow. This simple fix is therefore preferred for -stable backporting ]
On a system that implements FEATEPAN, read/write access to the idmap is denied because UXN is not set on the swapper PTEs. As a result, idmapkptiinstallngmappings panics the kernel when accessing _idmapkptiflag. Fix it by setting UXN on these PTEs.