[firesteelrain]

This is a problem and most people hadn’t considered it before because the caching is done to speed up build pipeline performance:

“ While rootless containers prevent the attacker from escalating to host root, the page cache is still shared across the host. Containers that re-use the same base image layers share the same cached pages for those layers — if a malicious CI job corrupts a binary in the page cache, other containers launched from that same image could end up executing the poisoned version.”

[dwattttt]

I'm no expert, but the kernel is shared between all containers and the host.

I don't believe the kernel maintains separate page caches for each container; a malicious CI job could corrupt a binary from any container, or the host.

[firesteelrain]

Only if there is a shared inode between host and container.

[duped]

Which is almost guaranteed if you're launching multiple containers with the same base image or shared layers.