A critical security flaw in current and older versions of the popular open source OpenX ad server allows attackers to remotely compromise a server. A few reports (German language link) even discuss successful attacks on OpenX servers in which the vulnerability was exploited.
Read the full article here.
Source:[TheHSecurity]
Hi, my report is also available in English:
Critical vulnerability in OpenX 2.8.6 & Open Flash Chart 2
It includes more details on how to fix the vulnerability quickly and what to do if your installation has already been compromised.