{
  "affected": [
    {
      "ranges": [
        {
          "events": [
            {
              "introduced": "a7878ca140084ec267ede48fce64d7e60f6d873e"
            },
            {
              "fixed": "163c16e01f53fc8eb8d0f3484ae6c382265ecbbd"
            },
            {
              "fixed": "436a214514e24103159aea455147d58b44a8a585"
            },
            {
              "fixed": "2b03ebbf8d5e8f6af4ecd6c65375232dd1ec32cc"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Linux",
        "name": "Kernel"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "4.12.0"
            },
            {
              "fixed": "6.18.52"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.19.0"
            },
            {
              "fixed": "7.2.6"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "Linux",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/90xxx/CVE-2026-90149.json"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nNFSv4/flexfiles: fix NULL dereference for NFSv4.0 data servers\n\nflexfiles accepts NFSv4.0 data servers, but two NFSv4 code paths assume\nthe data server client has a session. Unlike NFSv4.1+, an NFSv4.0 client\nhas no session (clp-\u003ecl_session is NULL; it uses clp-\u003ecl_slot_tbl), so\nI/O to a v4.0 flexfiles DS oopses:\n\n  - nfs4_init_ds_session() dereferences clp-\u003ecl_session-\u003esession_state\n    while seeding the DS lease. It also only seeds cl_lease_time when\n    NFS4_SESSION_INITING is set; without a session that never happens, so\n    cl_lease_time stays 0 and nfs4_renew_state() busy-loops, requeuing\n    every 5 seconds. Seed the lease whenever there is no session and\n    return before touching session state.\n\n  - ff_layout_async_handle_error_v4() dereferences\n    clp-\u003ecl_session-\u003efc_slot_table on every DS I/O error. Fall back to the\n    v4.0 transport slot table (clp-\u003ecl_slot_tbl) when there is no session.",
  "id": "CVE-2026-90149",
  "modified": "2026-09-18T03:30:32.994939282Z",
  "published": "2026-09-17T16:06:43.671Z",
  "references": [
    {
      "type": "PACKAGE",
      "url": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/163c16e01f53fc8eb8d0f3484ae6c382265ecbbd"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/2b03ebbf8d5e8f6af4ecd6c65375232dd1ec32cc"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/436a214514e24103159aea455147d58b44a8a585"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/90xxx/CVE-2026-90149.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-90149"
    }
  ],
  "schema_version": "1.9.0",
  "summary": "NFSv4/flexfiles: fix NULL dereference for NFSv4.0 data servers"
}