{
  "affected": [
    {
      "ecosystem_specific": {
        "urgency": "not yet assigned"
      },
      "package": {
        "ecosystem": "Debian:13",
        "name": "linux"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "ecosystem_specific": {
        "urgency": "not yet assigned"
      },
      "package": {
        "ecosystem": "Debian:14",
        "name": "linux"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "details": "In the Linux kernel, the following vulnerability has been resolved:  NFSD: Guard admin state-revocation walks with NFSD_NET_UP  Writing to /proc/fs/nfsd/unlock_filesystem, or sending the NFSD_CMD_UNLOCK_FILESYSTEM or NFSD_CMD_UNLOCK_EXPORT netlink command, walks the NFSv4 client hash tables to revoke open state and cancel async COPY operations.  All three handlers gate that walk on nn-\u003enfsd_serv, but a listener added via portlist or netlink listener_set sets nn-\u003enfsd_serv before any nfsd thread starts. nfsd_startup_net() has not yet allocated nn-\u003econf_id_hashtbl, so the walkers dereference a NULL table.  A local administrator with CAP_SYS_ADMIN can crash the kernel this way without ever starting the server.  nn-\u003enfsd_serv is set when the service is created, which precedes table allocation.  NFSD_NET_UP instead brackets the window where the tables are live: set at the end of nfsd_startup_net() and cleared in nfsd_shutdown_net() after they are freed, both under nfsd_mutex. Gating the three unlock paths on NFSD_NET_UP fixes the startup-time NULL dereference while preserving the earlier post-shutdown use-after-free fix.",
  "id": "DEBIAN-CVE-2026-90039",
  "modified": "2026-09-17T04:47:40.002272159Z",
  "published": "2026-09-16T11:17:17.110Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://security-tracker.debian.org/tracker/CVE-2026-90039"
    }
  ],
  "upstream": [
    "CVE-2026-90039"
  ]
}