Advisory Details

September 2nd, 2021

Microsoft Windows Lock Screen Improper Access Control Authentication Bypass Vulnerability

CVE ID	CVE-2021-26431
CVSS SCORE	6.8, AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
AFFECTED VENDORS	Microsoft
AFFECTED PRODUCTS	Windows
VULNERABILITY DETAILS	This vulnerability allows physically present attackers to bypass authentication on affected installations of Microsoft Windows. Authentication is not required to exploit this vulnerability. The specific flaw exists within the lock screen. The issue results from the lack of proper access control prior to authentication. An attacker can leverage this vulnerability to bypass authentication on the system.
ADDITIONAL DETAILS	Microsoft has issued an update to correct this vulnerability. More details can be found at: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-26431
DISCLOSURE TIMELINE	2021-06-30 - Vulnerability reported to vendor 2021-09-02 - Coordinated public release of advisory
CREDIT	Abdelhamid Naceri (halov)

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