>Of course, you’d want to try ../… Yes, it does let you escape the temporary folder...

This is absolute bull on seL4 by construction. "sandboxes" that prevent access that the OS otherwise grants. In seL4, this component would not need a sandbox in the first place, because it would never have a capability to some VFS path it doesn't need to access.

This sort of escape relies on ambient security, which is the security model of UNIX and Windows NT. Access is granted by default and then restricted, rather than simply not granted. A broken security model.

And, unlike a demonstrated shitty browser sandbox, seL4 formally guarantees isolation. Capabilities cannot be forged.