CVE-2026-97561 (GCVE-0-2026-97561)

Vulnerability from cvelistv5 – Published: 2026-09-25 10:21 – Updated: 2026-09-28 05:31
VLAI
Title
smb: client: honor forceuid/forcegid when mapping SIDs to uid/gid
Summary
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.
Severity
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 9409ae58e0759d010b347e7b19ebc90ab5d4b98f , < e1b74f8f8c1d13190b09fe623b729d36b7ac22a8 (git)
Affected: 9409ae58e0759d010b347e7b19ebc90ab5d4b98f , < 18a72975e9f35aadecc75b031f693f2d1f49308f (git)
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Linux Linux Affected: 3.0
Unaffected: 0 , < 3.0 (semver)
Unaffected: 7.2.7 , ≤ 7.2.* (semver)
Unaffected: 7.3-rc3 , ≤ * (original_commit_for_fix)
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{
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          "programFiles": [
            "fs/smb/client/cifsacl.c",
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          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nsmb: client: honor forceuid/forcegid when mapping SIDs to uid/gid\n\nWhen the administrator mounts with forceuid or forcegid (uid=/gid=\nmount options), they expect all files to appear owned by the specified\nuser/group.  However, several code paths unconditionally called\nsid_to_id() to overwrite cf_uid/cf_gid with server-provided values,\nignoring the administrator\u0027s explicit override:\n\n  - smb311_posix_info_to_fattr() (stat via POSIX extensions)\n  - cifs_posix_to_fattr() (readdir via POSIX extensions)\n  - parse_sec_desc() (CIFS ACL ownership mapping)\n\nThis allowed an untrusted server to dictate local file ownership even\nwhen the mount was configured to force specific uid/gid values.\n\nFix all three call sites to check CIFS_MOUNT_OVERR_UID and\nCIFS_MOUNT_OVERR_GID before calling sid_to_id(), following the\nsame pattern already used by cifs_unix_basic_to_fattr() for unix\nextensions."
        }
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      "providerMetadata": {
        "dateUpdated": "2026-09-28T05:31:07.986Z",
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    "assignerShortName": "Linux",
    "cveId": "CVE-2026-97561",
    "datePublished": "2026-09-25T10:21:50.067Z",
    "dateReserved": "2026-09-24T16:01:01.155Z",
    "dateUpdated": "2026-09-28T05:31:07.986Z",
    "state": "PUBLISHED"
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      "title": "smb: client: honor forceuid/forcegid when mapping SIDs to uid/gid",
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        "descriptions": [
          {
            "lang": "en",
            "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nsmb: client: honor forceuid/forcegid when mapping SIDs to uid/gid\n\nWhen the administrator mounts with forceuid or forcegid (uid=/gid=\nmount options), they expect all files to appear owned by the specified\nuser/group.  However, several code paths unconditionally called\nsid_to_id() to overwrite cf_uid/cf_gid with server-provided values,\nignoring the administrator\u0027s explicit override:\n\n  - smb311_posix_info_to_fattr() (stat via POSIX extensions)\n  - cifs_posix_to_fattr() (readdir via POSIX extensions)\n  - parse_sec_desc() (CIFS ACL ownership mapping)\n\nThis allowed an untrusted server to dictate local file ownership even\nwhen the mount was configured to force specific uid/gid values.\n\nFix all three call sites to check CIFS_MOUNT_OVERR_UID and\nCIFS_MOUNT_OVERR_GID before calling sid_to_id(), following the\nsame pattern already used by cifs_unix_basic_to_fattr() for unix\nextensions."
          }
        ],
        "id": "CVE-2026-97561",
        "lastModified": "2026-09-28T06:16:38.877",
        "metrics": {},
        "published": "2026-09-25T11:17:06.657",
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        ],
        "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "vulnStatus": "Received"
      }
    }
  }
}



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