CVE-2026-64392: ksmbd: use opener credentials for delete-on-close
In the Linux kernel, the following vulnerability has been resolved:
ksmbd: use opener credentials for delete-on-close
Delete-on-close can be completed by deferred or durable handle teardown, where no request work is available. Both the base-file unlink and the ADS xattr removal consequently run with the ksmbd worker credentials and can bypass filesystem permission checks.
Run both operations with the credentials captured in struct file when the handle was opened. This preserves the authenticated user's fsuid, fsgid, supplementary groups and capability restrictions at final close.
Affected Software
Remediation
Event History
Frequently Asked Questions
What is the severity of CVE-2026-64392?
The severity of CVE-2026-64392 is critical with a CVSS score of 9.1.
How do I fix CVE-2026-64392?
To fix CVE-2026-64392, you should update the Linux kernel to the latest stable version that addresses the vulnerability.
What does CVE-2026-64392 affect?
CVE-2026-64392 affects the ksmbd service in the Linux kernel concerning delete-on-close operations.
What kind of impact does CVE-2026-64392 have?
CVE-2026-64392 can allow unauthorized deletion of files due to improper handling of credentials during deferred or durable handle teardown.
When was CVE-2026-64392 published?
CVE-2026-64392 was published on July 25, 2026.