{
  "cveId": "CVE-2021-47506",
  "url": "https://patchblox.com/security/cve/CVE-2021-47506",
  "summary": "CVE-2021-47506 is fixed in linux on 1 platform, first by DEBIAN-CVE-2021-47506, released May 24, 2024. It is not reported as exploited. Patch Radar priority: High.",
  "title": "linux: In the Linux kernel, the following vulnerability has been resolved:  nfsd: fix use-after-free due to delegation race...",
  "description": "In the Linux kernel, the following vulnerability has been resolved:  nfsd: fix use-after-free due to delegation race  A delegation break could arrive as soon as we\u0027ve called vfs_setlease.  A delegation break runs a callback which immediately (in nfsd4_cb_recall_prepare) adds the delegation to del_recall_lru.  If we then exit nfs4_set_delegation without hashing the delegation, it will be freed as soon as the callback is done with it, without ever being removed from del_recall_lru.  Symptoms show up later as use-after-free or list corruption warnings, usually in the laundromat thread.  I suspect aba2072f4523 \u0022nfsd: grant read delegations to clients holding writes\u0022 made this bug easier to hit, but I looked as far back as v3.0 and it looks to me it already had the same problem.  So I\u0027m not sure where the bug was introduced; it may have been there from the beginning.",
  "published": "2024-05-24T15:15:11Z",
  "severity": "high",
  "cvss": 7.8,
  "cvssVector": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
  "epss": 0.00783,
  "epssPercentile": 0.56286,
  "priority": "High",
  "priorityTier": 3,
  "exploited": false,
  "vendorExploited": false,
  "disclosed": false,
  "fixes": [
    {
      "platform": "linux",
      "product": "linux",
      "release": "Debian 12.15 (bookworm)",
      "fixedVersion": "5.15.15-1",
      "fix": "DEBIAN-CVE-2021-47506",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2021-47506",
      "released": "2024-05-24T15:15:11Z"
    },
    {
      "platform": "linux",
      "product": "linux",
      "release": "Debian 13.5 (trixie)",
      "fixedVersion": "5.15.15-1",
      "fix": "DEBIAN-CVE-2021-47506",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2021-47506",
      "released": "2024-05-24T15:15:11Z"
    },
    {
      "platform": "linux",
      "product": "linux",
      "release": "Debian 14",
      "fixedVersion": "5.15.15-1",
      "fix": "DEBIAN-CVE-2021-47506",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2021-47506",
      "released": "2024-05-24T15:15:11Z"
    }
  ],
  "noFixYet": [],
  "dataAsOf": "2026-11-09T01:18:40Z",
  "attribution": {
    "text": "Data: Patchblox Patch Radar",
    "url": "https://patchblox.com/security/patch-radar",
    "terms": "https://patchblox.com/security/patch-radar/use-the-data"
  }
}