Privilege escalation in setuid mode via user namespaces in Bubblewrap
CVE-2020-5291

7.2HIGH

Key Information:

Vendor

Containers

Status
Bubblewrap
Vendor
CVE Published:
31 March 2020

What is CVE-2020-5291?

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 Version(s)

bubblewrap < 0.4.1

References

https://github.com/containers/bubblewrap/security/advisor...
x_refsource_CONFIRM
https://github.com/containers/bubblewrap/commit/1f7e2ad94...
x_refsource_MISC

CVSS V3.1

Score:
7.2
Severity:
HIGH
Confidentiality:
High
Integrity:
High
Availability:
High
Attack Vector:
Local
Attack Complexity:
High
Privileges Required:
Low
User Interaction:
Required
Scope:
Changed

Timeline

  • Vulnerability published

  • Vulnerability Reserved

.