The debian project defines a critical bug as “makes unrelated software on the system (or the whole system) break, or causes serious data loss, or introduces a security hole on systems where you install the package.”
FSF Europe reported that “Windows 7, is currently shipping with a potentially serious defect [...] a high-risk vulnerability in the SMB2 protocol. This can be exploited over the network to shut down a computer with a Denial of Service (DoS) attack.” (Full details)
You’d be hard pressed to know this from all the Windows 7 launch ra-ra on the BBC and others. Where was the Public Service part of the broadcast, warning customers about this awful problem?
Please, when picking your software, when choosing your next operating system, select one that is mainly cooperatively-developed and which makes a promise like “we will not hide problems”. debian, fedora and centos all make promises of openness. Check whether your system does and if it does, mention it in the comments here. If it doesn’t – please ask its developers!