Vdesk Hangupphp3 Exploit May 2026

While the vDesk HangupPHP3 exploit targets legacy systems, its consequences are severe:

| Impact Area | Description | |-------------|-------------| | Remote Code Execution (RCE) | Full control over the web server, allowing malware upload, data exfiltration, or pivoting to internal networks. | | Denial of Service | The race condition can corrupt session files for all users, effectively locking out entire helpdesk teams. | | Call Recording Theft | Attackers can download unencrypted call recordings stored by vDesk. | | Privilege Escalation | From a low-privileged agent account to the web server user, then potentially root via local exploits. | | VoIP Fraud | Using the compromised session, attackers can initiate outbound calls through the PBX integration. | vdesk hangupphp3 exploit

Several documented incidents in 2022–2024 show threat actors exploiting this vulnerability to deploy cryptocurrency miners on MSP helpdesk servers. While the vDesk HangupPHP3 exploit targets legacy systems,

The term "vdesk" suggests integration with Virtual Desktop Infrastructure (VDI) or a specific web-based telephony interface. The term "vdesk" suggests integration with Virtual Desktop

During the race, both processes try to call session_start() simultaneously. PHP’s default file-based session handler is not atomic. One process obtains a write lock, but the other executes session_write_close() prematurely. The session file becomes corrupted, containing partially unserialized data.