CVE-2020-5291: Archlinux Arch Linux

High severity, CVSS 7.8. EPSS: 0.9% chance of exploitation in the next 30 days.

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.

Affected products

• Archlinux Arch Linux: affected versions not specified
• Centos Centos: version 7.0 only
• Debian Debian Linux: version 10.0 only
• Projectatomic Bubblewrap: before 0.4.1 (fixed in 0.4.1)

Published 2020-03-31. Last modified 2026-06-17.