CVE-2026-64379 smb: client: mask server-provided mode to 07777 in modefromsid
A missing mask in the Linux kernel SMB client allows a malicious server to set arbitrary file permissions, potentially leading to privilege escalation.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-64379?
CVE-2026-64379 is a high-severity vulnerability in Linux kernel, published on 25 Jul 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official description
In the Linux kernel, the following vulnerability has been resolved:
smb: client: mask server-provided mode to 07777 in modefromsid
When modefromsid is active, parse_dacl() applies the server-provided sub_auth[2] value from the NFS mode SID to cf_mode without masking to 07777. Apply the correct masking, same as in the read path.
Weakness: CWE-20
Which versions are affected by CVE-2026-64379?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2026-64379?
Apply the vendor's patch.
Is CVE-2026-64379 being exploited?
There is no known exploitation of CVE-2026-64379 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as AZL-93647, BELL-CVE-2026-64379, DEBIAN-CVE-2026-64379, GHSA-fhph-rcwp-75hp, ROOT-OS-DEBIAN-12-CVE-2026-64379, ROOT-OS-UBUNTU-2204-CVE-2026-64379 and 1 more.