CVE-2016-6213: Medium severity Linux Linux kernel vulnerability
fs/namespace.c in the Linux kernel before 4.9 does not restrict how many mounts may exist in a mount namespace, which allows local users to cause a denial of service (memory consumption and deadlock) via MSBIND mount system calls, as demonstrated by a loop that triggers exponential growth in the number of mounts.
Other sources
It was found that in Linux kernel the mount table expands by a power-of-two with each bind mount command. If a system is configured to allow non-privileged user to do bind mounts, or allows to do so in a container or unprivileged mount namespace, then non-privileged user is able to cause a local DoS by overflowing the mount table, which causes a deadlock for the whole system.
CVE request:
http://seclists.org/oss-sec/2016/q3/56
Proofs:
http://seclists.org/oss-sec/2016/q3/65
http://seclists.org/oss-sec/2016/q3/75
Discussions:
https://lkml.org/lkml/2013/6/17/143
— Red Hat
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
debian/linuxto a version that resolves this vulnerability.Fixed in 5.10.223-1Fixed in 5.10.234-1Fixed in 6.1.129-1Fixed in 6.1.135-1Fixed in 6.12.25-1 - Upgrade
Upgrade
ubuntu/linuxto a version that resolves this vulnerability.Fixed in 3.13.0-106.153 - Upgrade
Upgrade
ubuntu/linux-lts-vividto a version that resolves this vulnerability.Fixed in 3.19.0-78.86~14.04.1 - Upgrade
Upgrade
ubuntu/linux-lts-xenialto a version that resolves this vulnerability.Fixed in 4.4.0-57.78~14.04.1 - Upgrade
Upgrade
ubuntu/linuxto a version that resolves this vulnerability.Fixed in 4.4.0-57.78 - Upgrade
Upgrade
ubuntu/linux-raspi2to a version that resolves this vulnerability.Fixed in 4.4.0-1038.45 - Upgrade
Upgrade
ubuntu/linux-snapdragonto a version that resolves this vulnerability.Fixed in 4.4.0-1042.46 - Upgrade
Upgrade
Linux kernelto a version that resolves this vulnerability.Fixed in 4.9
Event History
Frequently Asked Questions
What is CVE-2016-6213?
CVE-2016-6213 is a vulnerability in the Linux kernel that allows local users to cause a denial of service (memory consumption and deadlock) via MS_BIND mount system calls.
What is the severity of CVE-2016-6213?
The severity of CVE-2016-6213 is low.
How does CVE-2016-6213 affect Linux?
CVE-2016-6213 affects the Linux kernel versions before 4.9.
How can I fix CVE-2016-6213?
To fix CVE-2016-6213, update your Linux kernel to version 4.9 or later.
Where can I find more information about CVE-2016-6213?
You can find more information about CVE-2016-6213 at the following references: - [Reference 1](http://seclists.org/oss-sec/2016/q3/56) - [Reference 2](http://seclists.org/oss-sec/2016/q3/65) - [Reference 3](http://seclists.org/oss-sec/2016/q3/75)