In Helm before versions 2.16.11 and 3.3.2, a Helm plugin can contain duplicates of the same entry, with the last one always used. If a plugin is compromised, this lowers the level of access that an attacker needs to modify a plugin's install hooks, causing a local execution attack.
To perform this attack, an attacker must have write access to the git repository or plugin archive (.tgz) while being downloaded (which can occur during a MITM attack on a non-SSL connection). This issue has been patched in Helm 2.16.11 and Helm 3.3.2.
As a possible workaround make sure to install plugins using a secure connection protocol like SSL.
In Helm before versions 2.16.11 and 3.3.2 there is a bug in which the `alias` field on a `Chart.yaml` is not properly sanitized. This could lead to the injection of unwanted information into a chart. This issue has been patched in Helm 3.3.2 and 2.16.11. A possible workaround is to manually review the `dependencies` field of any untrusted chart, verifying that the `alias` field is either not used, or (if used) does not contain newlines or path characters.
In Helm 2.x before 2.15.2, commands that deal with loading a chart as a directory or packaging a chart provide an opportunity for a maliciously designed chart to include sensitive content such as /etc/passwd, or to execute a denial of service (DoS) via a special file such as /dev/urandom, via symlinks. No version of Tiller is known to be impacted. This is a client-only issue.