CVE-2026-109411 Samba: access control bypass via vfs_ceph_rgw case-insensitive open
- Exploited in the wild
- Not known
- Fix
- Available
What is CVE-2026-109411?
CVE-2026-109411 is a high-severity vulnerability in Red Hat Enterprise Linux 10, published on 28 Oct 2026.
Official description
An access control bypass flaw was identified in Samba's vfs_ceph_rgw module in it's openat() function. An authenticated user can bypass access controls to read or overwrite restricted files on shares configured with the experimental vfs_ceph_rgw module. When a client requests an existing file using mismatched character casing, the module fails to perform a case-insensitive lookup correctly, causing the server to treat the operation as creating a new file. As a result, the server skips standard permission checks on the existing file, allowing the attacker to access or overwrite sensitive data owned by other users.
Weakness: CWE-178
Which versions are affected by CVE-2026-109411?
Linux distribution packages (1)
samba openSUSE:Tumbleweed | All versions | 4.25.1+git.476.bfc358351cb-1.1 |
How do I fix CVE-2026-109411?
Upgrade to a fixed version.
Is CVE-2026-109411 being exploited?
There is no known exploitation of CVE-2026-109411 in the wild and no public exploit code.
Sources
Also known as DEBIAN-CVE-2026-109411, GHSA-pwp9-3h93-h2x8, UBUNTU-CVE-2026-109411, openSUSE-SU-2026:12334-1.