Vulnerability · Published Mar 31, 2020 · Assigned by GitHub_M
CVE-2020-5291Privilege escalation in setuid mode via user namespaces in Bubblewrap
High 7.2
In plain English
A high-severity security flaw in bubblewrap from containers. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.9% (higher than 60% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official 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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine:v3.20 | bubblewrap | 0.4.1-r0 | ALPINE-CVE-2020-5291 |
| Alpine:v3.21 | bubblewrap | 0.4.1-r0 | ALPINE-CVE-2020-5291 |
| Alpine:v3.22 | bubblewrap | 0.4.1-r0 | ALPINE-CVE-2020-5291 |
| Alpine:v3.23 | bubblewrap | 0.4.1-r0 | ALPINE-CVE-2020-5291 |
| Alpine:v3.24 | bubblewrap | 0.4.1-r0 | ALPINE-CVE-2020-5291 |
| Debian:12 | bubblewrap | 0.4.1-1 | DEBIAN-CVE-2020-5291 |
| Debian:13 | bubblewrap | 0.4.1-1 | DEBIAN-CVE-2020-5291 |
| Debian:14 | bubblewrap | 0.4.1-1 | DEBIAN-CVE-2020-5291 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| containers | bubblewrap | < 0.4.1 |
Weakness: CWE-648 · Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:C/C:H/I:H/A:N