This particular vulnerabilities use x86 specific instructions such as CPUID (which provides information about the CPU version) to extract the content of a share

This particular vulnerabilities use x86 specific instructions such as CPUID (which provides information about the CPU version) to extract the content of a shared buffer which contains sensitive data in some cases. This instruction (CPUID) is not accessible through JS within a web browser so there is probably no exploit from a web page. But this attack is feasible from any native application (without privileges) on the machine.