KubeAI is an AI inference operator for kubernetes. Prior to 0.23.2, the ollamaStartupProbeScript() function in internal/modelcontroller/engine_ollama.go constructs a shell command string using fmt.Sprintf with unsanitized model URL components (ref, modelParam). This shell command is executed via bash -c as a Kubernetes startup probe. An attacker who can create or update Model custom resources can inject arbitrary shell commands that execute inside model server pods. This vulnerability is fixed in 0.23.2.

Affected: Go: github.com/kubeai-project/kubeai

## CHAMP: Description

### Summary

The `ollamaStartupProbeScript()` function in `internal/modelcontroller/engine_ollama.go` constructs a shell command string using `fmt.Sprintf` with unsanitized model URL components (`ref`, `modelParam`). This shell command is executed via `bash -c` as a Kubernetes startup probe. An attacker who can create or update `Model` custom resources can inject arbitrary shell commands that execute inside model server pods.

### Details

The `parseModelURL()` function in `internal/modelcontroller/model_source.go` uses a regex (`^([a-z0-9]+):\/\/([^?]+)(\?.*)?$`) to parse model URLs. The `ref` component (capture group 2) matches `[^?]+`, allowing any characters except `?`, including shell metacharacters like `;`, `|`, `$()`, and backticks.

The `?model=` query parameter (`modelParam`) is also extracted without any sanitization.

**Vulnerable code** ([permalink](https://github.com/kubeai-project/kubeai/blob/ba1824e8c1d70c9092b6c0a48199bba3b8973fee/internal/modelcontroller/engine_ollama.go#L185-L196)):

```go func ollamaStartupProbeScript(m *kubeaiv1.Model, u modelURL) string { startupScript := "" if u.scheme == "pvc" { startupScript = fmt.Sprintf("/bin/ollama cp %s %s", u.modelParam, m.Name) } else { if u.pull { pullCmd := "/bin/ollama pull" if u.insecure { pullCmd += " --insecure" } startupScript = fmt.Sprintf("%s %s && /bin/ollama cp %s %s", pullCmd, u.ref, u.…