Microsoft Security Response Center guidance
Vendor revision: Nov 7, 2026Release Notes
Vendor-listed releases
- 6.6.161.1-1
Vulnerability intelligence
CVE-2026-97561. It is not in the current CISA KEV record we collected. That does not prove exploitation has not occurred.
Release Notes
Vendor-listed releases
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.
Source: NVD