Ubuntu Security Notice 5343-1 - Yiqi Sun and Kevin Wang discovered that the cgroups implementation in the Linux kernel did not properly restrict access to the cgroups v1 release_agent feature. A local attacker could use this to gain administrative privileges. It was discovered that the aufs file system in the Linux kernel did not properly restrict mount namespaces, when mounted with the non-default allow_userns option set. A local attacker could use this to gain administrative privileges.
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