Security researcher Alexander Popov has discovered and fixed five similar issues in the virtual socket implementation of the Linux kernel. The vulnerabilities could be exploited for local privilege escalation, as confirmed in experiments on Fedora 33 Server. These vulnerabilities result from race conditions that were implicitly added with virtual socket multi-transport support in November 2019. The patches have been merged into mainline kernel version 5.11-rc7 and backported into affected stable trees. The fix has been backported to mainline kernel versions of 5.5 and is now in stable.
Source: https://www.helpnetsecurity.com/2021/03/03/cve-2021-26708/