CVE-2026-64392 ksmbd: use opener credentials for delete-on-close
Attackers can bypass filesystem permission checks during file deletion in ksmbd, potentially modifying or deleting files with elevated privileges.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-64392?
CVE-2026-64392 is a critical vulnerability in Linux kernel, published on 25 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
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.
Which versions are affected by CVE-2026-64392?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2026-64392?
Apply the vendor's patch.
Is CVE-2026-64392 being exploited?
There is no known exploitation of CVE-2026-64392 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2026-64392, DEBIAN-CVE-2026-64392, GHSA-cq4q-mqm3-8r2p, ROOT-OS-DEBIAN-12-CVE-2026-64392, ROOT-OS-UBUNTU-2204-CVE-2026-64392, UBUNTU-CVE-2026-64392.