There's a vulnerability in the CRI-O application where when container is launched with securityContext.runAsUser specifying a non-existent user, CRI-O attempts to create the user, reading the container's entire /etc/passwd file into memory. If this file is excessively large, it can cause the a high memory consumption leading applications to be killed due to out-of-memory. As a result a denial-of-service can be achieved, possibly disrupting other pods and services running in the same host.
Credits
Red Hat would like to thank Dongha Kim (BoB Project Team, Pirates) for reporting this issue.
