It indicates a attacker attempted a Buffer Overflow attack against the Icecast streaming server. Icecast is vulnerable to a Buffer Overflow exploit because it does not check bounds on user supplied data. It is possible for an attacker to send a long string to the server causing an overflow leading to the execution of arbitrary code.
Icecast Icecast 1.3.11
Compromise of the affected system.
Apply appropriate patch from the vendor or Upgrade to non-vulnerable version if available.