If you've downloaded IPB 2.1.5 since the time of this post, there is no need to update your installation as the main download has been updated.
It has come to our attention that Invision Power Board 2.0.x and Invision Power Board 2.1.x contains potential vulnerabilities:
- Potential SQL injection (limited to 32 characters)
- Potential arbitrary PHP code execution
Invision Power Board 2.1.x Update Package
Invision Power Board 2.0.x Update Package
Source: Click Here