# CVE-2020-5291: bubblewrap: Bubblewrap (bwrap) before version 0.4.1, if installed in setuid mode and the kernel supports unprivileged user namesp...

CVE-2020-5291 is fixed in bubblewrap on 1 platform by bubblewrap 0.4.0-1ubuntu4 (version 0.4.0-1ubuntu4), released March 31, 2020. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2020-5291
- Priority: Routine
- CVSS: n/a (Low)
- EPSS: 0.0090
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Mar 31, 2020

## 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.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | bubblewrap Ubuntu 20.04 LTS (focal) | 0.4.0-1ubuntu4 | [bubblewrap 0.4.0-1ubuntu4](https://patchblox.com/security/data/fix/linux/ubuntu-focal-bubblewrap-0.4.0-1ubuntu4.md) | Mar 31, 2020 |

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