CVE-2020-5291

Name	CVE-2020-5291
Description	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.
Source	CVE (at NVD; CERT, LWN, oss-sec, fulldisc, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)
Debian Bugs	955441

Vulnerable and fixed packages

The table below lists information on source packages.

Source Package	Release	Version	Status
bubblewrap (PTS)	buster	0.3.1-4	fixed
	bullseye	0.4.1-3	fixed
	bookworm	0.8.0-2	fixed
	sid, trixie	0.9.0-1	fixed

The information below is based on the following data on fixed versions.

Package	Type	Release	Fixed Version	Urgency	Debian Bugs
bubblewrap	source	stretch	(not affected)
bubblewrap	source	buster	(not affected)
bubblewrap	source	(unstable)	0.4.1-1	low	955441

Notes

[buster] - bubblewrap <not-affected> (Introduced in 0.4.0)
[stretch] - bubblewrap <not-affected> (Introduced in 0.4.0)
https://github.com/containers/bubblewrap/security/advisories/GHSA-j2qp-rvxj-43vj
https://github.com/containers/bubblewrap/commit/1f7e2ad948c051054b683461885a0215f1806240