Executive brief
A security vulnerability exists in the Windows Server Message Block (SMB) protocol, which is used for sharing files and printers across a network. An attacker who already has basic access to a computer could exploit this flaw to view sensitive information that they should not be able to see. This could lead to the exposure of confidential system data or user information, though it does not allow the attacker to take control of the system or delete files.
Technical details
A vulnerability classified as CWE-908 (Use of Uninitialized Resource) exists within the Microsoft Windows SMB implementation. The flaw is triggered when the system fails to properly initialize a memory buffer or resource before it is used or returned to a user. An attacker with local access and low privileges can exploit this to read uninitialized memory, potentially disclosing sensitive system information or kernel data. The attack requires local authentication but no user interaction. Microsoft has released security updates to address this issue across affected Windows 10, 11, and Server 2012 versions.
Affected products
- Microsoft Windows 10 1607, 1809, 21H2, 22H2
- Microsoft Windows 11 24H2, 25H2, 26H1
- Microsoft Windows Server 2012 All versions
Timeline
- 2026-07-14: disclosed
- 2026-07-14: advisory: Microsoft published the security update guide.