backpack/crud provides Create, Read, Update & Delete (CRUD) functions for Backpack, a collection of Laravel packages that help users build custom administration panels. Prior to 4.1.70, 5.6.2, 6.8.13, and 7.0.36, Backpack\CRUD\Stats::makeCurlRequest in src/Stats.php is reached from BackpackServiceProvider::boot() and constructs a shell command with a URL influenced by the HTTP Host header, which it passes to exec() without adequate shell neutralization. An unauthenticated attacker whose malformed Host value reaches PHP can inject operating-system commands when exec() and curl are available and the 1-in-100 random gate is reached. Repeated requests can reach the random gate. Successful exploitation executes commands as the web-server user, exposing environment secrets, files, and reachable services and permitting data modification or service disruption. Common reverse-proxy Host validation and hardened PHP configurations that disable exec() reduce reachability but do not correct the vulnerable construction. This issue is fixed in versions 4.1.70, 5.6.2, 6.8.13, and 7.0.36.

Affected: Packagist: backpack/crud

## Summary

`Backpack\CRUD\Stats::makeCurlRequest` builds a shell command using unescaped input that originates from the HTTP `Host` header, then passes it to `exec()`. A specially crafted Host header can break out of the shell argument and cause the server to execute arbitrary OS commands as the web user.

The vulnerable code path is reached from `BackpackServiceProvider::boot()` on every HTTP request in production when `exec()` and `curl` are available. A 1-in-100 random gate is the only guard — an attacker can reliably trigger it by retrying.

## Severity

**High — CVSS 8.1** `CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H`

Attack Complexity is rated **High** because default nginx and Apache configurations typically strip or reject malformed Host headers before they reach PHP, and `exec()` is often disabled for web processes in hardened environments. Both mitigations must be absent for exploitation.

## Impact

A successful exploit yields OS command execution as the web server user (`www-data`, `nginx`, etc.), giving an unauthenticated attacker access to environment secrets (APP_KEY, database credentials, API keys in `.env`), the filesystem, and any service the server can reach.

## Fix

`makeCurlRequest` was replaced with the Guzzle-based path already present in the codebase, eliminating the shell-command construction entirely. **Upgrade to a patched release immediately.**

## Affected versions

| Branch | Vulnerable range | First safe version | |--------|--------------…