MantisBT is a free and open source web-based bug tracking system written in PHP and works with MySQL, MS SQL, and PostgreSQL databases and a webserver.  It is created to aid product bug tracking. It has been installed on Windows, Linux, Mac OS, OS/2, and others. Almost any web browser should be able to function as a client.

Features of Mantis:
- Simple User Experience
- Web Based
- Supports any platform that runs PHP (Windows, Linux, Mac, Solaris, AS400/i5, etc)
- Available in 68 localizations.
- Simple/Advanced Issue Pages
- Multiple Projects per instance
- Support for Projects, Sub-Projects, and Categories.
- Users can have a different access level per project
- Changelog Support
- Roadmap
- My View Page
- Search and Filter
- Full Text Search
- Simple/Advanced Filters
- Shared Filters (across users / projects)
- Built-in Reporting (reports / graphs)
- Custom Fields
- Email notifications
- Users can monitor specific issues
- Attachments (can be saved on webserver or in database can also backup to an FTP account)
- Issue Change History
- RSS Feeds (news, issues matching saved filters, issues matching a specific project)
- Customizable issue workflow
- Sponsorships Support users are able to place bounties or sponsorships for specific issues, also developers can track such sponsorships / payments.
- Anonymous Access
- Signup with Captcha and Email Confirmation.
- Self-Service Reset Password Support
- Export to csv, Microsoft Excel, Microsoft Word
- Ability to extended functionality through hook (custom) functions.

Requirements:
- PHP 5.2.0 and Higher
- MySQL database 4.1.1 and Higher (MS SQL, DB2, and PostgreSQL are also supported).
- Web server (Apache, IIS, etc.)

What's New in This Version:
- Any malicious user could use the view issues page (search.php) to execute a filter that could bring down the site by overloading the database server (CVE-2013-1883). Affects MantisBT 1.2.12 and later.
- A cross site scripting (XSS) vulnerability allowed execution of arbitrary JavaScript code when deleting a version. Affects MantisBT 1.2.14 and later.