This indicates an attempt to exploit a remote Code Execution vulnerability in in the Bassmaster nodejs plugin for hapi.
The vulnerability is due to insufficient sanitizing of user supplied inputs while handling maliciously crafted HTTP request. A remote attacker can exploit this to execute remote code on a targeted system via a crafted HTTP request.
Bassmaster plugin 1.5.1 and prior version
System Compromise: Remote attackers can gain control of vulnerable systems.
Apply the most recent upgrade or patch from the vendor.