Privilege escalation in setuid mode via ptrace. If bubblewrap is installed in setuid mode then the user can use ptrace to attach to bubblewrap and control the unprivileged part of the sandbox setup phase. This allows it the attacker to arbitrarily use the privileged operations, and in particular the "overlay mount" operation, allowing the creation of overlay mounts which is otherwise not allowed in the setuid version of bubblewrap. The support for overlayfs mounts was added in version 0.11.0. Versions before that did not support overlay mounts, so are not affected.