CVE-2020-5291

Bubblewrap (bwrap) before version 0.4.1, if installed in setuid mode and
the kernel supports unprivileged user namespaces, then the bwrap --userns2 option can be used to make the setuid process keep running as
root while being traceable. This can in turn be used to gain root
permissions. Note that this only affects the combination of bubblewrap in
setuid mode (which is typically used when unprivileged user namespaces are
not supported) and the support of unprivileged user namespaces. Known to be
affected are: * Debian testing/unstable, if unprivileged user namespaces
enabled (not default) * Debian buster-backports, if unprivileged user
namespaces enabled (not default) * Arch if using linux-hardened, if
unprivileged user namespaces enabled (not default) * Centos 7 flatpak COPR,
if unprivileged user namespaces enabled (not default) This has been fixed
in the 0.4.1 release, and all affected users should update.

Bugs

• <http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=955441&gt;

Notes