Details
On 2 September 2020, vulnerability CVE-2020-14386 was made public, disclosing a memory corruption problem with the Linux kernel. More details on this can be found at the following URL:
https://access.redhat.com/security/cve/cve-2020-14386
Currently this only effects RHEL8 systems so if you are using CentOS 7 or RHEL 7 you are not vulnerable.
Additionally, if you are running the KernelCare software on your system, there is already a patch available, with more details here:
https://blog.kernelcare.com/patch-cve-2020-14386-without-reboot-with-kernelcare
Testing
If you are using RHEL8 or CentOS 8 you can run the following command to confirm if your system is vulnerable:
# sysctl user.max_user_namespaces
user.max_user_namespaces = 15000
Any value reported here other than "0" would indicate the system is vulnerable. Until an updated kernel is available, setting that value to "0" will effectively mitigate the issue.