This is a collection of all major known security advisory feeds per operating system or topic. It is a superset of the 2010 post at geekscrap.com which misses Linux specific feeds. The idea is for you to grab the links below and drop those you need in your favourite feed reader (even Thunderbird will do). Alternatively you can pay others to do it for you :-) If you find broken links please post a comment below!

Unix / Linux Distributions

Application Specific

Platforms/Middleware

Collections

By Vendor

How to get a feed for software not listed here?

1. Check cvedetails.com

When you need a security feed not listed above visit http://cvedetails.com and search for the product or vendor you are interested in. If you find it and recent CVEs are listed click on "Vulnerability Feeds and Widgets" which opens up a dialog where you can configure a filter and click "Generate RSS Feed". Note: If you don't find the "Vulnerability Feed and Widgets" link ensure you are on the "Vulnerability Statistics" page of the product/vendor!

2. Check gmane.org

If it is an open source product you are looking for and it has a security related mailing list chances are high that is being tracked by gmane.org which provides RSS feeds for each mailing list.