FKIE_CVE-2026-97554

Vulnerability from fkie_nvd - Published: 2026-09-25 11:17 - Updated: 2026-09-28 06:16
Severity
Summary
In the Linux kernel, the following vulnerability has been resolved: smb: client: avoid using uninitialized SIDs in cifs_posix_to_fattr() cifs_posix_to_fattr() ignores the return value of posix_info_parse(). When a malformed POSIX directory entry is encountered (e.g. invalid SID lengths from an untrusted server), posix_info_parse() returns -1 without populating the 'parsed' struct. The uninitialized stack memory in parsed.owner and parsed.group is then passed to sid_to_id(), which processes the garbage bytes and passes them to request_key() to construct a SID string, potentially leaking kernel stack contents to the userspace idmap daemon. Fix this by checking the return value and skipping the SID-to-id mapping when parsing fails. The remaining fattr fields (timestamps, mode, etc.) are populated directly from the 'info' pointer so they are unaffected.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/c9a8b60ce140a68d172452f418137fc7ddbae7db
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/da6e25842431982d5a53cf00d925b98c690f4467
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/smb/client/readdir.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "c9a8b60ce140a68d172452f418137fc7ddbae7db",
              "status": "affected",
              "version": "9934430e2178d5164eb1ac91a9b092f9e7e64745",
              "versionType": "git"
            },
            {
              "lessThan": "da6e25842431982d5a53cf00d925b98c690f4467",
              "status": "affected",
              "version": "9934430e2178d5164eb1ac91a9b092f9e7e64745",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "dd80b98bdf0a4b3206739f3513b0518f27a7b4ef",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "d8e39c11f66125f49de55537a6efc8ecadf4a0f7",
              "versionType": "git"
            },
            {
              "lessThan": "5.9",
              "status": "affected",
              "version": "5.8.17",
              "versionType": "semver"
            },
            {
              "lessThan": "5.10",
              "status": "affected",
              "version": "5.9.2",
              "versionType": "semver"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "fs/smb/client/readdir.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.10"
            },
            {
              "lessThan": "5.10",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.7",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3-rc3",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nsmb: client: avoid using uninitialized SIDs in cifs_posix_to_fattr()\n\ncifs_posix_to_fattr() ignores the return value of posix_info_parse().\nWhen a malformed POSIX directory entry is encountered (e.g. invalid\nSID lengths from an untrusted server), posix_info_parse() returns -1\nwithout populating the \u0027parsed\u0027 struct.  The uninitialized stack\nmemory in parsed.owner and parsed.group is then passed to\nsid_to_id(), which processes the garbage bytes and passes them to\nrequest_key() to construct a SID string, potentially leaking kernel\nstack contents to the userspace idmap daemon.\n\nFix this by checking the return value and skipping the SID-to-id\nmapping when parsing fails.  The remaining fattr fields (timestamps,\nmode, etc.) are populated directly from the \u0027info\u0027 pointer so they\nare unaffected."
    }
  ],
  "id": "CVE-2026-97554",
  "lastModified": "2026-09-28T06:16:38.783",
  "metrics": {},
  "published": "2026-09-25T11:17:05.860",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/c9a8b60ce140a68d172452f418137fc7ddbae7db"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/da6e25842431982d5a53cf00d925b98c690f4467"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}



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