CVEvulnerability
CVE-2026-97561
- Status
- Received
- Published
- 2026-09-25
- Last modified
- 2026-10-21
- Assigner
- 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Description
In the Linux kernel, the following vulnerability has been resolved:
smb: client: honor forceuid/forcegid when mapping SIDs to uid/gid
When the administrator mounts with forceuid or forcegid (uid=/gid=
mount options), they expect all files to appear owned by the specified
user/group. However, several code paths unconditionally called
sid_to_id() to overwrite cf_uid/cf_gid with server-provided values,
ignoring the administrator's explicit override:
- smb311_posix_info_to_fattr() (stat via POSIX extensions)
- cifs_posix_to_fattr() (readdir via POSIX extensions)
- parse_sec_desc() (CIFS ACL ownership mapping)
This allowed an untrusted server to dictate local file ownership even
when the mount was configured to force specific uid/gid values.
Fix all three call sites to check CIFS_MOUNT_OVERR_UID and
CIFS_MOUNT_OVERR_GID before calling sid_to_id(), following the
same pattern already used by cifs_unix_basic_to_fattr() for unix
extensions.
References
- https://git.kernel.org/stable/c/18a72975e9f35aadecc75b031f693f2d1f49308f git.kernel.org
- https://git.kernel.org/stable/c/6ac7a29691558bed18e2df1780636b8aa0fd13d5 git.kernel.org
- https://git.kernel.org/stable/c/bc35de451c128d399ad185d6269f8847e97cd1c9 git.kernel.org
- https://git.kernel.org/stable/c/be6eccccec867c22d7c65fab4ea4e91ec3d5b8c6 git.kernel.org
- https://git.kernel.org/stable/c/e1b74f8f8c1d13190b09fe623b729d36b7ac22a8 git.kernel.org