Executive brief
A vulnerability in the Linux Network File System (NFS) service allows authorized users to bypass security restrictions and access files they should not be able to see. Specifically, a user with basic access to a shared folder can gain unauthorized access to any subfolder or file within that share, ignoring standard security settings like 'root_squash'. This could lead to the exposure of sensitive data stored on corporate file servers.
Technical details
A vulnerability exists in the rpc.mountd daemon within the nfs-utils package for Linux. The flaw allows an authenticated NFSv3 client to escalate privileges assigned in the /etc/exports file at mount time. By exploiting this, a client can access any subdirectory or subtree of an exported directory, bypassing file permissions and security attributes such as 'root_squash' or 'all_squash'. The issue is tracked as CWE-732 (Incorrect Permission Assignment) and CWE-279. Patches have been released by Red Hat for RHEL 8, 9, and 10.
Affected products
- Red Hat Enterprise Linux 8 Fixed in 1:2.3.3-68.el8_10
- Red Hat Enterprise Linux 9 Fixed in 1:2.5.4-38.el9_7.3
- Red Hat Enterprise Linux 10 Fixed in 1:2.8.3-0.el10_1.3
- Linux nfs-utils
Timeline
- 2026-03-04: disclosed
- 2026-03-05: patched: Red Hat released security updates (RHSA-2026:3938, RHSA-2026:3939)
References
- https://access.redhat.com/downloads/content/package-browser/
- https://catalog.redhat.com/software/containers/
- https://access.redhat.com/errata/RHSA-2026:3938
- https://access.redhat.com/errata/RHSA-2026:3939
- https://access.redhat.com/errata/RHSA-2026:3940
- https://access.redhat.com/errata/RHSA-2026:3941
- https://access.redhat.com/errata/RHSA-2026:3942