CVE-2026-97564 (GCVE-0-2026-97564)
Vulnerability from cvelistv5
Published
2026-09-25 10:21
Modified
2026-10-19 09:09
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved: smb: client: reject userspace cifs.idmap descriptions cifs.idmap key descriptions carry authority-bearing fields (owner and group SIDs and uid/gid values in "os:"/"gs:"/"oi:"/"gi:" form) that the cifs.idmap upcall helper treats as kernel-originating inputs. Unlike its sibling cifs.spnego, the cifs.idmap key type has no vet_description hook, so userspace can create keys of this type through request_key(2)/add_key(2) and supply those fields without CIFS origin. A request_key(2) call with a non-NULL callout then drives a root usermodehelper upcall (/sbin/request-key -> cifs.idmap) that consumes the unvetted description in root context. Only accept cifs.idmap descriptions while CIFS is using its private root_cred to request the key. id_to_sid()/sid_to_id() already run under override_creds(root_cred), so the kernel-originated path is unaffected. This mirrors commit 3da1fdf4efbc ("smb: client: reject userspace cifs.spnego descriptions"), which applied the same restriction to cifs.spnego.
References
Impacted products
Vendor Product Version
Linux Linux Version: 4d79dba0e00749fa40de8ef13a9b85ce57a1603b
Version: 4d79dba0e00749fa40de8ef13a9b85ce57a1603b
Version: 4d79dba0e00749fa40de8ef13a9b85ce57a1603b
Version: 4d79dba0e00749fa40de8ef13a9b85ce57a1603b
Version: 4d79dba0e00749fa40de8ef13a9b85ce57a1603b
Version: 4d79dba0e00749fa40de8ef13a9b85ce57a1603b
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{
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          "programFiles": [
            "fs/smb/client/cifsacl.c"
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          "vendor": "Linux",
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              "versionType": "original_commit_for_fix"
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      ],
      "cpeApplicability": [
        {
          "nodes": [
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              "negate": false,
              "operator": "OR"
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      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nsmb: client: reject userspace cifs.idmap descriptions\n\ncifs.idmap key descriptions carry authority-bearing fields (owner and\ngroup SIDs and uid/gid values in \"os:\"/\"gs:\"/\"oi:\"/\"gi:\" form) that the\ncifs.idmap upcall helper treats as kernel-originating inputs.  Unlike\nits sibling cifs.spnego, the cifs.idmap key type has no vet_description\nhook, so userspace can create keys of this type through\nrequest_key(2)/add_key(2) and supply those fields without CIFS origin.\nA request_key(2) call with a non-NULL callout then drives a root\nusermodehelper upcall (/sbin/request-key -\u003e cifs.idmap) that consumes\nthe unvetted description in root context.\n\nOnly accept cifs.idmap descriptions while CIFS is using its private\nroot_cred to request the key.  id_to_sid()/sid_to_id() already run\nunder override_creds(root_cred), so the kernel-originated path is\nunaffected.\n\nThis mirrors commit 3da1fdf4efbc (\"smb: client: reject userspace\ncifs.spnego descriptions\"), which applied the same restriction to\ncifs.spnego."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-19T09:09:27.178Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/f29c1ec0e7d8c887a91df3f93bb4617c0ac95c6a"
        },
        {
          "url": "https://git.kernel.org/stable/c/17c93bcd17755523c21abb22cbf2a41a6eb0caaf"
        },
        {
          "url": "https://git.kernel.org/stable/c/e5964064e3fbe6325893408faff08ca33de0e2c3"
        },
        {
          "url": "https://git.kernel.org/stable/c/96751028c0d4dec785709ea3eb0ab38a4f2ded96"
        },
        {
          "url": "https://git.kernel.org/stable/c/1d3b24b16a0b013792e8f1e3ed060f0b46f537d1"
        },
        {
          "url": "https://git.kernel.org/stable/c/d9d7eeb0cea5b55b82888f443622fd8d4ee064f3"
        }
      ],
      "title": "smb: client: reject userspace cifs.idmap descriptions",
      "x_generator": {
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      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-97564",
    "datePublished": "2026-09-25T10:21:51.858Z",
    "dateReserved": "2026-09-24T16:01:01.155Z",
    "dateUpdated": "2026-10-19T09:09:27.178Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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