Code: static UINT drdynvc_process_create_request(drdynvcPlugin* drdynvc, int Sp,
        int cbChId, wStream* s)
{
	size_t pos;
	UINT status;
 	UINT32 ChannelId;
 	wStream* data_out;
 	UINT channel_status;
 
 	if (!drdynvc)
 		return CHANNEL_RC_BAD_CHANNEL_HANDLE;

	if (drdynvc->state == DRDYNVC_STATE_CAPABILITIES)
	{
		/**
		 * For some reason the server does not always send the
		 * capabilities pdu as it should. When this happens,
		 * send a capabilities response.
		 */
		drdynvc->version = 3;

		if ((status = drdynvc_send_capability_response(drdynvc)))
		{
			WLog_Print(drdynvc->log, WLOG_ERROR, "drdynvc_send_capability_response failed!");
			return status;
		}

 		drdynvc->state = DRDYNVC_STATE_READY;
 	}
 
 	ChannelId = drdynvc_read_variable_uint(s, cbChId);
 	pos = Stream_GetPosition(s);
 	WLog_Print(drdynvc->log, WLOG_DEBUG, "process_create_request: ChannelId=%"PRIu32" ChannelName=%s",
	           ChannelId,
	           Stream_Pointer(s));
	channel_status = dvcman_create_channel(drdynvc, drdynvc->channel_mgr, ChannelId,
	                                       (char*) Stream_Pointer(s));
 	data_out = Stream_New(NULL, pos + 4);
 
 	if (!data_out)
	{
		WLog_Print(drdynvc->log, WLOG_ERROR, "Stream_New failed!");
		return CHANNEL_RC_NO_MEMORY;
	}

	Stream_Write_UINT8(data_out, 0x10 | cbChId);
	Stream_SetPosition(s, 1);
	Stream_Copy(s, data_out, pos - 1);

	if (channel_status == CHANNEL_RC_OK)
	{
		WLog_Print(drdynvc->log, WLOG_DEBUG, "channel created");
		Stream_Write_UINT32(data_out, 0);
	}
	else
	{
		WLog_Print(drdynvc->log, WLOG_DEBUG, "no listener");
		Stream_Write_UINT32(data_out, (UINT32)0xC0000001); /* same code used by mstsc */
	}

	status = drdynvc_send(drdynvc, data_out);

	if (status != CHANNEL_RC_OK)
	{
		WLog_Print(drdynvc->log, WLOG_ERROR, "VirtualChannelWriteEx failed with %s [%08"PRIX32"]",
		           WTSErrorToString(status), status);
		return status;
	}

	if (channel_status == CHANNEL_RC_OK)
	{
		if ((status = dvcman_open_channel(drdynvc, drdynvc->channel_mgr, ChannelId)))
		{
			WLog_Print(drdynvc->log, WLOG_ERROR, "dvcman_open_channel failed with error %"PRIu32"!", status);
			return status;
		}
	}
	else
	{
		if ((status = dvcman_close_channel(drdynvc->channel_mgr, ChannelId)))
			WLog_Print(drdynvc->log, WLOG_ERROR, "dvcman_close_channel failed with error %"PRIu32"!", status);
	}

	return status;
}

Vulnerability Type: 
CWE ID: 
Summary: FreeRDP FreeRDP 2.0.0-rc3 released version before commit 205c612820dac644d665b5bb1cdf437dc5ca01e3 contains a Other/Unknown vulnerability in channels/drdynvc/client/drdynvc_main.c, drdynvc_process_capability_request that can result in The RDP server can read the client's memory.. This attack appear to be exploitable via RDPClient must connect the rdp server with echo option. This vulnerability appears to have been fixed in after commit 205c612820dac644d665b5bb1cdf437dc5ca01e3.
Commit Message: Fix for #4866: Added additional length checks