Executive brief
Windows SMB Client, a core networking component used by millions of computers to share files and printers on corporate networks, contains a buffer over-read vulnerability. An attacker on the network could exploit this flaw to read sensitive information from affected systems' memory without requiring authentication, potentially exposing credentials, business data, or other confidential information.
Technical details
A buffer over-read vulnerability exists in the Windows SMB Client networking implementation. The flaw allows an attacker to read beyond allocated memory boundaries via a specially crafted SMB protocol message sent over the network. No authentication or user interaction is required; an attacker positioned on the same network segment or with network access to an SMB client can trigger the vulnerability to disclose sensitive information from process memory. The vulnerability is a classic information disclosure class defect with a CVSS score of 6.5 (medium severity). Microsoft has released security patches to address this issue.
Affected products
- Microsoft Windows SMB Client
Timeline
- 2026-08-11: disclosed