These copyfail exploits allow an unprivileged (daemon/app) user (not in sudoers) to get root without interaction from the original system maintainer.
It's quite different from PATH-injecting an already privileged user.
Also, these memory corruptions can likely be used as container escape primitives too. Albeit not easily.
It's a serious break of a security boundary. Yes, container layer adds defense, and normal unix security isn't perfect, but it should not allow this.
Copy Fail can't affect files it can't access.
PoC attack on k8s [1] claims execution through sibling layers of kube-proxy, host filesystem access through /dev/ [2].
[1] https://github.com/Percivalll/Copy-Fail-CVE-2026-31431-Kuber...
[2] https://github.com/Percivalll/Copy-Fail-CVE-2026-31431-Kuber...