kernel: rtnetlink: add missing netlink_ns_capable() check for peer netns

A flaw was found in the Linux kernel's rtnetlink component. An unprivileged local user, leveraging a user namespace, can exploit a missing CAPNETADMIN capability check in the rtnlnewlink function. This allows the user to create paired network devices in arbitrary network namespaces, including the...

UBUNTU-CVE-2021-46912

In the Linux kernel, the following vulnerability has been resolved: net: Make tcpallowedcongestioncontrol readonly in non-init netns Currently, tcpallowedcongestioncontrol is global and writable; writing to it in any net namespace will leak into all other net namespaces...