all SET commands to haproxy socket fail with : Permission denied

[Piavlo]

 Hi,
Tried with several 1.4.* versions including latest, the get commands 
work and for set commands there is  - Permission denied

# echo "get weight common_slave/slave1a" | socat stdio 
/var/lib/haproxy/stats
25 (initial 25)

# echo "set weight common_slave/slave1a 50%" | socat stdio 
/var/lib/haproxy/stats
Permission denied


Any ideas?

Thanks