Microsoft's Patch Tuesday borks dual-boot Linux-Windows PCs

Plus: Three-year-old ProxyLogon flaw added to CISA's exploited bugs list

Microsoft says it's investigating issues with a patch intended to plug a two-year-old flaw in the GRUB open source boot loader that is crashing some dual-boot computers running both Windows and Linux. In that crash users are aptly told: "Something went seriously wrong."…