{
  "affected": [
    {
      "ranges": [
        {
          "events": [
            {
              "introduced": "620c266f394932e5decc4b34683a75dfc59dc2f4"
            },
            {
              "fixed": "15104234c267ebe04b9f9a73e5c2179cc265ff60"
            },
            {
              "fixed": "6c52226072a3c61337b1eec1799bb987748884fa"
            },
            {
              "fixed": "6ee183d89261bf1d1cf9f06d80a40dab8f36ee55"
            },
            {
              "fixed": "6c732471740bc2ac9b0946134f9f551dc75f4369"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Linux",
        "name": "Kernel"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "6.11.0"
            },
            {
              "fixed": "6.12.97"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.13.0"
            },
            {
              "fixed": "6.18.40"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.19.0"
            },
            {
              "fixed": "7.1.5"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "Linux",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/72xxx/CVE-2026-72034.json"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nfhandle: reject detached mounts in capable_wrt_mount()\n\nThe recent fhandle RCU fix moved the mount namespace capability check\ninto capable_wrt_mount(), so a non-NULL mnt_namespace survives the\nns_capable() dereference. The helper still assumes the later\nREAD_ONCE(mount-\u003emnt_ns) must be non-NULL because may_decode_fh()\nchecked is_mounted() first.\n\nThat assumption is not stable. A detached mount from\nopen_tree(..., OPEN_TREE_CLONE) can be dissolved on fput while\nopen_by_handle_at() is between those checks, and umount_tree() can\nclear mount-\u003emnt_ns. If the helper observes NULL, it dereferences\nmnt_ns-\u003euser_ns and panics.\n\nReturn false when the RCU read observes a detached mount. This keeps\nthe relaxed permission path conservative: a mount no longer attached\nto a namespace cannot authorize open_by_handle_at() access.",
  "id": "CVE-2026-72034",
  "modified": "2026-08-18T03:30:49.666922160Z",
  "published": "2026-08-15T05:51:55.739Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/15104234c267ebe04b9f9a73e5c2179cc265ff60"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/6c52226072a3c61337b1eec1799bb987748884fa"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/6c732471740bc2ac9b0946134f9f551dc75f4369"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/6ee183d89261bf1d1cf9f06d80a40dab8f36ee55"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/72xxx/CVE-2026-72034.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-72034"
    },
    {
      "type": "PACKAGE",
      "url": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
    }
  ],
  "schema_version": "1.9.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "fhandle: reject detached mounts in capable_wrt_mount()"
}