{
  "affected": [
    {
      "ranges": [
        {
          "events": [
            {
              "introduced": "349e13ad30b45998bb9937cfe0b32be6f951976d"
            },
            {
              "fixed": "171605aed68380c2fa75dff9b3a1ed427c50065b"
            },
            {
              "fixed": "4213c1208978483021d7d125c131de3985d38f61"
            },
            {
              "fixed": "96e889bc1e759c83f25093e8c2f3da31b4973f30"
            },
            {
              "fixed": "0de5b8e76847f5de26f364a82c6602c4881c30da"
            },
            {
              "fixed": "427eb7eb46425fec845a43e861f3d6e2899cae59"
            },
            {
              "fixed": "86c5d470f5d42e61123b2f4b4f0b91f4eee5b980"
            },
            {
              "fixed": "46a84715a015cb48e1b9c219dc88c03d8a541ea4"
            },
            {
              "fixed": "7ad2bcf2441430bb2e918fb3ef9a90d775a6e422"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Linux",
        "name": "Kernel"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "5.7.0"
            },
            {
              "fixed": "5.10.261"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "5.11.0"
            },
            {
              "fixed": "5.15.212"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "5.16.0"
            },
            {
              "fixed": "6.1.178"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.2.0"
            },
            {
              "fixed": "6.6.145"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.7.0"
            },
            {
              "fixed": "6.12.96"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.13.0"
            },
            {
              "fixed": "6.18.39"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.19.0"
            },
            {
              "fixed": "7.1.4"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "Linux",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/64xxx/CVE-2026-64380.json"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nsmb: client: harden POSIX SID length parsing\n\nposix_info_sid_size() reads sid[1] to obtain the subauthority count,\nbut its existing boundary check still accepts buffers with only one\nremaining byte. Require two bytes before reading sid[1] so all client\npaths that reuse the helper reject truncated POSIX SIDs safely.",
  "id": "CVE-2026-64380",
  "modified": "2026-08-18T03:31:11.179581853Z",
  "published": "2026-07-25T08:50:30.476Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/0de5b8e76847f5de26f364a82c6602c4881c30da"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/171605aed68380c2fa75dff9b3a1ed427c50065b"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/4213c1208978483021d7d125c131de3985d38f61"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/427eb7eb46425fec845a43e861f3d6e2899cae59"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/46a84715a015cb48e1b9c219dc88c03d8a541ea4"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/7ad2bcf2441430bb2e918fb3ef9a90d775a6e422"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/86c5d470f5d42e61123b2f4b4f0b91f4eee5b980"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/96e889bc1e759c83f25093e8c2f3da31b4973f30"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/64xxx/CVE-2026-64380.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-64380"
    },
    {
      "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:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "smb: client: harden POSIX SID length parsing"
}