CVE-2020-5291: Privilege escalation in setuid mode via user namespaces in Bubblewrap
First published: Tue Mar 31 2020(Updated: )
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.
Credit: security-advisories@github.com
| Affected Software | Affected Version | How to fix |
|---|---|---|
| Projectatomic Bubblewrap | <0.4.1 | |
| Debian Debian Linux | =10.0 | |
| Archlinux Arch Linux | ||
| CentOS CentOS | =7.0 |
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Reference Links
Frequently Asked Questions
What is CVE-2020-5291?
CVE-2020-5291 is a vulnerability in the Bubblewrap (bwrap) software before version 0.4.1.
Is Bubblewrap affected by CVE-2020-5291?
Yes, Bubblewrap before version 0.4.1 is affected by CVE-2020-5291.
What is the severity of CVE-2020-5291?
CVE-2020-5291 has a severity rating of 7.8 (high).
How can CVE-2020-5291 be exploited?
CVE-2020-5291 can be exploited by using the `bwrap --userns2` option, which allows a setuid process to keep running as root while being traceable, leading to potential root privilege escalation.
How can I fix CVE-2020-5291?
To fix CVE-2020-5291, update Bubblewrap to version 0.4.1 or later.
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