Comodo Antivirus versions 11.0.0.6582 and below are vulnerable to Denial of Service affecting CmdGuard.sys via its filter port \cmdServicePort\. A low privileged process can crash CmdVirth.exe to decrease the port's connection count followed by process hollowing a CmdVirth.exe instance with malicious code to obtain a handle to \cmdServicePort\. Once this occurs a specially crafted message can be sent to \cmdServicePort\ using \FilterSendMessage\ API. This can trigger an out-of-bounds write if lpOutBuffer parameter in FilterSendMessage API is near the end of specified buffer bounds. The crash occurs when the driver performs a memset operation which uses a size beyond the size of buffer specified causing kernel crash.