GHSA-hr2v-4r36-88hr
Helm Chart extraction output directory collapse via `Chart.yaml` name dot-segment
Packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| Go | helm.sh/helm/v4 | < 4.1.4 | 4.1.4 |
| Go | helm.sh/helm/v3 | < 3.20.2 | 3.20.2 |
Details
As written in the advisory (Markdown source, shown as plain text).
Helm is a package manager for Charts for Kubernetes. In Helm versions <=3.20.1 and <=4.1.3, a specially crafted Chart will cause `helm pull --untar [chart URL | repo/chartname]` to write the Chart's contents to the immediate output directory (as defaulted to the current working directory; or as given by the `--destination` and `--untardir` flags), rather than the expected output directory suffixed by the chart's name.
### Impact
The bug enables writing the Chart's contents (unpackaged/untar'ed) to the output directory `<output dir>/`, instead of the expected `<output dir>/<chart name>/`, potentially overwriting the contents of the targeted directory.
Note: a chart name containing POSIX dot-dot, or dot-dot and slashes (as if to refer to parent directories) do not resolve beyond the output directory as designed.
### Patches
This issue has been resolved in Helm v3.20.2 and v4.1.3
A Chart with an unexpected name (those specified to be "." or ".."), or a Chart name which results in a non-unique directory will be rejected.
### Workarounds
Ensure the the name of the Chart does not comprise/contain POSIX pathname special directory references ie. dot-dot ("..") or dot ("."). In addition, ensuring that the `pull --untar` flag (or equivalent SDK option) refers to a unique/empty output directory prevents chart extraction from inadvertently overwriting existing files within the specified directory.
### Credits
Oleh Konko
@1seal
References
External links from the advisory. They lead to third-party sites.