{
  "affected": [
    {
      "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: fix null dereference in nfsd4_setattr for deleg timestamp attrs  When a SETATTR request includes FATTR4_WORD2_TIME_DELEG_ACCESS or FATTR4_WORD2_TIME_DELEG_MODIFY in the attribute bitmap, nfsd4_setattr() sets deleg_attrs=true and calls nfs4_preprocess_stateid_op() to validate the stateid.  If the client supplies the NFSv4 \"one stateid\" (all-0xFF bytes), check_special_stateids() returns nfs_ok without populating the output nfs4_stid pointer, because the special-stateid path in nfs4_preprocess_stateid_op() jumps to done: with s==NULL, and the \"if (s)\" block that would set *cstid is skipped. The local variable `st` remains NULL.  Back in nfsd4_setattr(), the if (deleg_attrs) block then unconditionally dereferences st-\u003esc_type (at offset 4 from NULL), causing a kernel oops.  This is remotely triggerable by any NFSv4 client: send COMPOUND [PUTROOTFH, SETATTR(ONE_STATEID, {bmval2=FATTR4_WORD2_TIME_DELEG_ACCESS, ...})]. No authentication, delegation, or prior state is required.  Fix by adding a NULL check before the dereference. A special stateid is not a delegation stateid, so the existing nfserr_bad_stateid return value is already correct; we only need to guard the pointer dereference itself.",
  "id": "DEBIAN-CVE-2026-89679",
  "modified": "2026-09-14T08:47:31.393888459Z",
  "published": "2026-09-11T20:19:54.660Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://security-tracker.debian.org/tracker/CVE-2026-89679"
    }
  ],
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ],
  "upstream": [
    "CVE-2026-89679"
  ]
}