OliveTin gives access to predefined shell commands from a web interface. In versions up to and including 3000.10.0, OliveTin's shell mode safety check (`checkShellArgumentSafety`) blocks several dangerous argument types but not `password`. A user supplying a `password`-typed argument can inject shell metacharacters that execute arbitrary OS commands. A second independent vector allows unauthenticated RCE via webhook-extracted JSON values that skip type safety checks entirely before reaching `sh -c`. When exploiting vector 1, any authenticated user (registration enabled by default, `authType: none` by default) can execute arbitrary OS commands on the OliveTin host with the permissions of the OliveTin process. When exploiting vector 2, an unauthenticated attacker can achieve the same if the instance receives webhooks from external sources, which is a primary OliveTin use case. When an attacker exploits both vectors, this results in unauthenticated RCE on any OliveTin instance using Shell mode with webhook-triggered actions. As of time of publication, a patched version is not available.

Affected: Go: github.com/OliveTin/OliveTin

### Summary

OliveTin's shell mode safety check (`checkShellArgumentSafety`) blocks several dangerous argument types but not `password`. A user supplying a `password`-typed argument can inject shell metacharacters that execute arbitrary OS commands. A second independent vector allows unauthenticated RCE via webhook-extracted JSON values that skip type safety checks entirely before reaching `sh -c`.

### Details

**Vector 1 — `password` type bypasses shell safety check (PR:L)**

`service/internal/executor/arguments.go` has two gaps:

```go // Line 198-199 — TypeSafetyCheck returns nil (no error) for password type case "password": return nil // accepts ANY string including ; | ` $()

// Line 313 — checkShellArgumentSafety blocks dangerous types but not password unsafe := map[string]bool{ "url": true, "email": true, "raw_string_multiline": true, "very_dangerous_raw_string": true, // "password" is absent — not blocked } ```

Shell execution at `service/internal/executor/executor_unix.go:18`: ```go exec.CommandContext(ctx, "sh", "-c", finalParsedCommand) ```

A user supplies a `password` argument value of `'; id; echo '` → `sh -c` interprets the shell metacharacters → arbitrary command execution.

This is not the "admin already has access" pattern: OliveTin explicitly enforces an admin/user boundary where admins define commands and users only supply argument values. The `password` type is the documented, intende…