{
  "affected": [
    {
      "ranges": [
        {
          "events": [
            {
              "introduced": "e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9"
            },
            {
              "fixed": "cf2148b880fb7c0fcd727202dbc4fd5d6998b9c2"
            },
            {
              "fixed": "b5b5d5936a50497fb151c0b122899a6894721c2b"
            },
            {
              "fixed": "08f9e6d899b5c834bbcc239eae1bed58d9b15d2c"
            },
            {
              "fixed": "d2454f4a002d08560a60f214f392e6491cf11560"
            },
            {
              "fixed": "46bbcd3ebfb3549c8da1838fc4493e79bd3241e7"
            },
            {
              "fixed": "9401f86a224f37b50e6a3ccf1d46a70d5ef8af0a"
            },
            {
              "fixed": "53370cf9090777774e07fd9a8ebce67c6cc333ab"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Linux",
        "name": "Kernel"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "5.15.0"
            },
            {
              "fixed": "6.1.175"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.2.0"
            },
            {
              "fixed": "6.6.136"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.7.0"
            },
            {
              "fixed": "6.12.83"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.13.0"
            },
            {
              "fixed": "6.18.24"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.19.0"
            },
            {
              "fixed": "6.19.14"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.20.0"
            },
            {
              "fixed": "7.0.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "Linux",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/31xxx/CVE-2026-31611.json"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: require 3 sub-authorities before reading sub_auth[2]\n\nparse_dacl() compares each ACE SID against sid_unix_NFS_mode and on\nmatch reads sid.sub_auth[2] as the file mode.  If sid_unix_NFS_mode is\nthe prefix S-1-5-88-3 with num_subauth = 2 then compare_sids() compares\nonly min(num_subauth, 2) sub-authorities so a client SID with\nnum_subauth = 2 and sub_auth = {88, 3} will match.\n\nIf num_subauth = 2 and the ACE is placed at the very end of the security\ndescriptor, sub_auth[2] will be  4 bytes past end_of_acl.  The\nout-of-band bytes will then be masked to the low 9 bits and applied as\nthe file's POSIX mode, probably not something that is good to have\nhappen.\n\nFix this up by forcing the SID to actually carry a third sub-authority\nbefore reading it at all.",
  "id": "CVE-2026-31611",
  "modified": "2026-07-08T05:36:58.136729766Z",
  "published": "2026-04-24T14:42:32.124Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/08f9e6d899b5c834bbcc239eae1bed58d9b15d2c"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/46bbcd3ebfb3549c8da1838fc4493e79bd3241e7"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/53370cf9090777774e07fd9a8ebce67c6cc333ab"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/9401f86a224f37b50e6a3ccf1d46a70d5ef8af0a"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/b5b5d5936a50497fb151c0b122899a6894721c2b"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/cf2148b880fb7c0fcd727202dbc4fd5d6998b9c2"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/d2454f4a002d08560a60f214f392e6491cf11560"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/31xxx/CVE-2026-31611.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-31611"
    },
    {
      "type": "PACKAGE",
      "url": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
    }
  ],
  "schema_version": "1.7.5",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "ksmbd: require 3 sub-authorities before reading sub_auth[2]"
}