PinchTab is a standalone HTTP server that gives AI agents direct control over a Chrome browser. PinchTab `v0.8.4` contains a Windows-only command injection issue in the orphaned Chrome cleanup path. When an instance is stopped, the Windows cleanup routine builds a PowerShell `-Command` string using a `needle` derived from the profile path. In `v0.8.4`, that string interpolation escapes backslashes but does not safely neutralize other PowerShell metacharacters. If an attacker can launch an instance using a crafted profile name and then trigger the cleanup path, they may be able to execute arbitrary PowerShell commands on the Windows host in the security context of the PinchTab process user. This is not an unauthenticated internet RCE. It requires authenticated, administrative-equivalent API access to instance lifecycle endpoints, and the resulting command execution inherits the permissions of the PinchTab OS user rather than bypassing host privilege boundaries. Version 0.8.5 contains a patch for the issue.

Affected: Go: github.com/pinchtab/pinchtab/cmd/pinchtab, Go: github.com/pinchtab/pinchtab

### Summary PinchTab `v0.8.4` contains a Windows-only command injection issue in the orphaned Chrome cleanup path. When an instance is stopped, the Windows cleanup routine builds a PowerShell `-Command` string using a `needle` derived from the profile path. In `v0.8.4`, that string interpolation escapes backslashes but does not safely neutralize other PowerShell metacharacters.

If an attacker can launch an instance using a crafted profile name and then trigger the cleanup path, they may be able to execute arbitrary PowerShell commands on the Windows host in the security context of the PinchTab process user.

This is not an unauthenticated internet RCE. It requires authenticated, administrative-equivalent API access to instance lifecycle endpoints, and the resulting command execution inherits the permissions of the PinchTab OS user rather than bypassing host privilege boundaries.

### Details **Issue 1 — PowerShell command string built with interpolated user-influenced data (`internal/bridge/cleanup_windows.go` in `v0.8.4`):**

``` func findPIDsByPowerShell(needle string) []int { escaped := strings.ReplaceAll(needle, `\`, `\\`) cmd := exec.Command("powershell", "-NoProfile", "-Command", fmt.Sprintf(`Get-CimInstance Win32_Process -Filter "Name='chrome.exe'" | `+ `Where-Object { $_.CommandLine -like '*%s*' } | `+ `Select-Object -ExpandProperty ProcessId`, escaped)) } ```

The `needle` value is interpolated directly into a PowerShell comm…