{
  "id": "CVE-2026-98284",
  "url": "https://spydr.io/cve/CVE-2026-98284",
  "published": "2026-10-06T09:18:18.480Z",
  "modified": "2026-10-06T09:18:18.480Z",
  "score": null,
  "severity": null,
  "cvss_version": null,
  "vector": null,
  "score_source": null,
  "epss": 0.00162,
  "epss_percentile": 0.04842,
  "exploited": false,
  "kev": null,
  "ssvc_exploitation": null,
  "vendors": [
    "Linux"
  ],
  "products": [
    "Linux"
  ],
  "cwes": [],
  "description": "In the Linux kernel, the following vulnerability has been resolved: netlink: do not free nlk->groups while lockless readers can use it netlink_realloc_groups() uses krealloc() under netlink_table_grab(). Whenever NLGRPSZ(groups) lands in a different kmalloc bucket, the old bitmap is freed immediately. Two readers of nlk->groups / nlk->ngroups do not hold the netlink table lock: 1) sk_diag_dump_groups(). Hashed (bound) sockets are dumped from the rhashtable walk in __netlink_diag_dump(), which only holds RCU. Only the mc_list part of the dump takes nl_table_lock. 2) netlink_native_seq_show() (/proc/net/netlink), whose walk has been lockless since commit 21e4902aea80 (\"netlink: Lockless lookup with RCU grace period in socket release\"). Both can read a freed buffer, and sk_diag_dump_groups() can also read past the end of the old (smaller) buffer if it happens to load the old @groups pointer together with the new @ngroups value, copying the result into a NETLINK_DIAG_GROUPS attribute. This is the same class of bug that commit f773608026ee (\"netlink: access nlk groups safely in netlink bind and getname\") fixed for bind() and getname(); these two readers were missed. Simply grabbing the table lock in sk_diag_dump_groups() is not an option, because it is also called with nl_table_lock already held from the mc_list section of the dump. Make the lockless readers safe instead: - Allocate a new bitmap and free the old one after an RCU grace period, instead of relying on the implicit kfree() done by krealloc(). - Publish @groups before @ngroups, both with release semantics, and have the lockless readers load @ngroups first. A reader can then never pair the new (bigger) size with the old (smaller) buffer, and a reader picking up the new pointer while still seeing the old size is guaranteed to see the initialized bitmap. netlink_realloc_groups() is called from process context (bind() and setsockopt()), so kfree_rcu_mightsleep() can be used, once the table has been released.",
  "status": "Received",
  "score_type": null,
  "scores": {
    "cvss_v40": null,
    "cvss_v31": null,
    "cvss_v30": null
  },
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/22f313e211d58a66786c81487c3905fa5d4b2a8f",
      "tags": []
    },
    {
      "url": "https://git.kernel.org/stable/c/ceac0de741bfb47ca255eee075257b3bb31f0651",
      "tags": []
    }
  ],
  "nvd_url": "https://nvd.nist.gov/vuln/detail/CVE-2026-98284",
  "covered_in": [],
  "attribution": [
    {
      "source": "NVD",
      "url": "https://nvd.nist.gov",
      "notice": "This product uses data from the NVD API but is not endorsed or certified by the NVD."
    },
    {
      "source": "CISA KEV",
      "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog",
      "notice": "Known exploited vulnerabilities from the CISA KEV catalog."
    },
    {
      "source": "FIRST EPSS",
      "url": "https://www.first.org/epss",
      "notice": "Exploit prediction scores from FIRST EPSS."
    }
  ]
}