https://www.theregister.co.uk/2018/04/04/microsoft_windows_defender_rar_bug/
A remote-code execution vulnerability in Windows Defender – a flaw that can be exploited by malicious .rar files to run malware on PCs – has been traced back to an open-source archiving tool Microsoft adopted for its own use.
[...] Apparently, Microsoft forked that version of unrar and incorporated the component into its operating system's antivirus engine. That forked code was then modified so that all signed integer variables were converted to unsigned variables, causing knock-on problems with mathematical comparisons. This in turn left the software vulnerable to memory corruption errors, which can crash the antivirus package or allow malicious code to potentially execute.
(Score: 0) by Anonymous Coward on Tuesday April 10 2018, @03:51AM
That doesn't sound like FOSS. That's proprietary with access to source code.
So people, beginning with Microsoft, lay all the blame for Microsoft's screw-up on FOSS, when the code wasn't even FOSS to begin with? Typical.