Executive brief
A security vulnerability exists in the Windows SMB Client, a component used by Windows computers to connect to file shares and printers over a network. An attacker who already has basic access to a system could exploit this flaw to gain full administrative control. This could allow them to steal sensitive data, install malicious software, or disrupt business operations on the affected machine.
Technical details
A use-after-free vulnerability (CWE-416) exists within the Microsoft Windows SMB Client driver. The flaw is triggered when the system incorrectly manages memory objects during SMB communication, allowing an attacker to reuse a memory pointer after it has been freed. To exploit this, an attacker must first have local access to the system with low-level privileges. Successful exploitation allows the attacker to execute arbitrary code with elevated system privileges. Microsoft has assigned a CVSS score of 7.0, noting high complexity for successful exploitation.
Affected products
- Microsoft Windows SMB Client
Timeline
- 2026-05-12: disclosed
- 2026-05-12: advisory