[Coverity](http://www.coverity.com) has published it’s [Open Source Scan Report 2008](http://coverity.com/library/pdf/Coverity-Scan_Open_Source_Report_2008.pdf), which details the security status of several open source projects. Here’s my summary:
* The overall security of open source projects is improving.
* There’s a linear relationship between the amount of code and the amount of bugs.
* Surprisingly, there’s no relation between function length and defect density.
Projects with exceptionally low defect density include Amanda, NTP, OpenPAM, OpenVPN, Perl, PHP, Python, TCL, Postfix, Samba, curl, libvorbis and vim.
The top two security defects are
1. NULL pointer dereference
2. Resource leak
I got to preview [Coverity Prevent](http://www.coverity.com/html/prod_prevent.html) at a previous job, and it rocks at finding real bugs in code, with a very low rate of false positives.