In Germany they recommend to use it only in well ventilated areas and suggest to refrain from using it indoors. I take this as itīs not considered save to do so.
There is a lot of truth in this,
caution is warranted,
burning produces carbon monoxide, 
so you need to ventilate,
have stove on stable surface,
away from curtains ,
away from pets,
don't leave fire unattended,
don't drink alcohol or stuff like that,
keep children away from stove,
use carbon monoxide / smoke detector,
have fire extinguisher ready,
...
there is risk to everything 
and the cheapest legal pants  

is to say don't take the risk at all
easier than convincing 
people knowitalls to take precautions
but if you take a few simple precautions risk can be minimizedThis is what a book on wood/coal... cookstoves has to say about ventilation
Figure 20 - CO and average PM level reduction by ventilation
Closed Kitchen              CO Average (ppm) 54
Hole in Roof                CO Average (ppm) 18  reduction  of 67% 
Window and Hole in Roof     CO Average (ppm) 14  reduction  of 75% 
Door Open                   CO Average (ppm) 1   reduction  of 97% 
Kitchen Dimensions:
10 ft (3 m) wide X 8 ft (2.4 m) deep X 6 ft (1.8 m) high X
8 ft (2.4 m) peak
Door: 2 ft (0.6 m) X 6 ft (1.8 m)
Window: 11 in (0.28 m) X 14 in (0.36 m)
Hole in Roof: 9.8 in (0.25 m) X 7.9 in (0.2 m)
Stove height: 2 ft. (0.6 m)
Book also has a Cookstove Safety Ratings worksheet
This is short preview of article that takes a closer look emissions from camping stoves in a tent sized space
 Stoves, Tents and Carbon Monoxide - Deadly or Not? Part 5: Laboratory Measurements for 
Solid Fuels - Backpacking Light 
I don't expect any surprises 

burning produces emissions, 
too much fuel burns more dirty, 
pot sitting in flames produces more emissions,
...
you need to ventilateupdate:
Concentration 	Symptoms
35 ppm (0.0035%) 	Headache and dizziness within six to eight hours of constant exposure
100 ppm (0.01%) 	Slight headache in two to three hours
200 ppm (0.02%) 	Slight headache within two to three hours; loss of judgment
400 ppm (0.04%) 	Frontal headache within one to two hours
800 ppm (0.08%) 	Dizziness, nausea, and convulsions within 45 min; insensible within 2 hours
1,600 ppm (0.16%) 	Headache, increased heart rate, dizziness, and nausea within 20 min; death in less than 2 hours
3,200 ppm (0.32%) 	Headache, dizziness and nausea in five to ten minutes. Death within 30 minutes.
6,400 ppm (0.64%) 	Headache and dizziness in one to two minutes. Convulsions, respiratory arrest, and death in less than 20 minutes.
12,800 ppm (1.28%) 	Unconsciousness after 23 breaths. Death in less than three minutes.
Concentration 	Source
0.1 ppm 	Natural atmosphere level (MOPITT)
0.5 to 5 ppm 	Average level in homes
5 to 15 ppm 	Near properly adjusted gas stoves in homes
100 to 200 ppm 	Exhaust from automobiles in the Mexico City central area
5,000 ppm 	Exhaust from a home wood fire
7,000 ppm 	Undiluted warm car exhaust without a catalytic converter
30,000 ppm 	Afterdamp following an explosion in a coal mine