HTB Connected Complete Writeup - CVE-2025-57819 FreePBX Pre-Auth RCE, PHP Webshell, Incron Abuse & fwconsole-commands Hook PrivEsc

A comprehensive penetration testing guide exploiting CVE-2025-57819 for unauthenticated remote code execution on FreePBX 16.0.40.7 via SQL injection into cron_jobs, deploying a PHP webshell, and escalating to root by abusing an incron-triggered sysadmin_manager hook with a zlib+base64 encoded payload that bypasses character sanitization.

May 31, 2026 • views • 24 min read • 2,501 words

By

Havoc

hackthebox 26 htb 30 linux 11 freepbx cve-2025-57819 rce 8 sql-injection 2 php-webshell 2 incron cron-abuse privilege-escalation 17 authentication-bypass 2 payload-encoding easy-difficulty 2 season11 3 asterisk pbx