It is possible to craft an environment variable with newlines to add entries to a container's /etc/passwd. It is possible to circumvent admission validation of username/UID by adding such an entry.
Note: because the pod author is in control of the container's /etc/passwd, this is not considered a new risk factor. However, this advisory is being opened for transparency and as a way of tracking fixes.
1.26.0 will have the fix. More patches will be posted as they're available.
Additional security controls like SELinux should prevent any damage a container is able to do with root on the host. Using SELinux is recommended because this class of attack is already possible by manually editing the container's /etc/passwd
{
"nvd_published_at": "2023-09-25T20:15:10Z",
"cwe_ids": [
"CWE-538",
"CWE-913"
],
"github_reviewed_at": "2022-12-29T01:49:47Z",
"severity": "MODERATE",
"github_reviewed": true
}