{
  "cveId": "CVE-2026-98983",
  "url": "https://patchblox.com/security/cve/CVE-2026-98983",
  "summary": "CVE-2026-98983 is fixed in linux on 1 platform by DEBIAN-CVE-2026-98983 (version 7.2.11-1), released October 24, 2026. It is not reported as exploited. Patch Radar priority: Routine.",
  "title": "linux: In the Linux kernel, the following vulnerability has been resolved:  unshare: don\u0027t drop active namespace references...",
  "description": "In the Linux kernel, the following vulnerability has been resolved:  unshare: don\u0027t drop active namespace references that were never taken  Active references on the namespaces of an nsproxy are taken when the nsproxy is installed into a task in switch_task_namespaces() and copy_namespaces() and dropped again by put_nsproxy() through deactivate_nsproxy().  But ksys_unshare() calls put_nsproxy() on an nsproxy that was never installed when set_cred_ucounts() fails. The new namespaces of that nsproxy go from zero to minus one and the namespaces shared with the caller lose a reference that belongs to the nsproxy the caller keeps using:    WARNING: kernel/nscommon.c:171 at __ns_ref_active_put\u002B0x1cd/0x230    nsproxy_ns_active_put    deactivate_nsproxy    ksys_unshare  Afterwards the namespaces the caller lives in aren\u0027t listed by listns() anymore. set_cred_ucounts() only fails when alloc_ucounts() can\u0027t allocate and it only allocates when the real uid of the caller differs from its effective uid.  Commit cefd55bd2159 (\u0022nsproxy: fix free_nsproxy() and simplify create_new_namespaces()\u0022) separated the two cases on purpose. nsproxy_free() frees an nsproxy that was prepared but never installed and that\u0027s what a failed setns() uses in put_nsset(). Export it and use it for a failed unshare() as well.",
  "published": "2026-10-23T13:17:20Z",
  "severity": "",
  "epss": 0.00163,
  "epssPercentile": 0.05507,
  "priority": "Routine",
  "priorityTier": 4,
  "exploited": false,
  "vendorExploited": false,
  "disclosed": false,
  "fixes": [
    {
      "platform": "linux",
      "product": "linux",
      "release": "Debian 14",
      "fixedVersion": "7.2.11-1",
      "fix": "DEBIAN-CVE-2026-98983",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2026-98983",
      "released": "2026-10-24T13:25:57Z"
    }
  ],
  "noFixYet": [],
  "dataAsOf": "2026-11-09T07:25:28Z",
  "attribution": {
    "text": "Data: Patchblox Patch Radar",
    "url": "https://patchblox.com/security/patch-radar",
    "terms": "https://patchblox.com/security/patch-radar/use-the-data"
  }
}