CVE-2026-64391: ksmbd: use opener credentials for ADS I/O
In the Linux kernel, the following vulnerability has been resolved:
ksmbd: use opener credentials for ADS I/O
Alternate data streams are stored as xattrs. Unlike regular file I/O, their read and write paths therefore call VFS xattr helpers which recheck inode permissions and LSM policy using the current task credentials.
Run ADS I/O with the credentials captured when the SMB handle was opened.
Affected Software
Remediation
Event History
Frequently Asked Questions
What is the severity of CVE-2026-64391?
CVE-2026-64391 has a critical severity rating of 9.8 according to the CVSS 3.1 metrics.
What systems are affected by CVE-2026-64391?
CVE-2026-64391 affects the Linux kernel, specifically impacting ksmbd functionality.
How do I fix CVE-2026-64391?
To fix CVE-2026-64391, update your Linux kernel to the latest version that addresses this vulnerability.
What type of vulnerability is CVE-2026-64391?
CVE-2026-64391 is a vulnerability related to the use of opener credentials for Alternate Data Streams (ADS) I/O.
What is the potential impact of exploiting CVE-2026-64391?
Exploitation of CVE-2026-64391 could allow unauthorized access to sensitive data through mismanaged file permissions.