Microsoft's patches for the Meltdown vulnerability have had a fatal flaw all these past months, according to Alex Ionescu, a security researcher with cyber-security firm Crowdstrike.
Only patches for Windows 10 versions were affected, the researcher wrote today in a tweet. Microsoft quietly fixed the issue on Windows 10 Redstone 4 (v1803), also known as the April 2018 Update, released on Monday.
"Welp, it turns out the Meltdown patches for Windows 10 had a fatal flaw: calling NtCallEnclave returned back to user space with the full kernel page table directory, completely undermining the mitigation," Ionescu wrote.
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Ionescu pointed out that older versions of Windows 10 are still running with outdated and bypass-able Meltdown patches.
