GHSA-HH4G-5Q85-W496

Vulnerability from github – Published: 2026-08-15 06:32 – Updated: 2026-08-15 06:32
VLAI
Details

In the Linux kernel, the following vulnerability has been resolved:

netfilter: xt_cluster: reject template conntracks in hash match

xt_cluster_mt() treats any non-NULL nf_ct_get() result as a fully initialized conntrack and passes it to xt_cluster_hash().

This causes a state confusion bug when the raw table CT target attaches a template conntrack to skb->_nfct before normal conntrack processing. Templates carry IPS_TEMPLATE status but do not have a valid tuple for hashing yet, so xt_cluster_hash() can hit its WARN_ON() path on the zeroed l3num field.

Reject template conntracks before hashing them. This matches existing netfilter handling for template objects and avoids hashing incomplete conntrack state.

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{
  "affected": [],
  "aliases": [
    "CVE-2026-72256"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-08-15T06:21:53Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: xt_cluster: reject template conntracks in hash match\n\nxt_cluster_mt() treats any non-NULL nf_ct_get() result as a fully\ninitialized conntrack and passes it to xt_cluster_hash().\n\nThis causes a state confusion bug when the raw table CT target attaches\na template conntrack to skb-\u003e_nfct before normal conntrack processing.\nTemplates carry IPS_TEMPLATE status but do not have a valid tuple for\nhashing yet, so xt_cluster_hash() can hit its WARN_ON() path on the\nzeroed l3num field.\n\nReject template conntracks before hashing them. This matches existing\nnetfilter handling for template objects and avoids hashing incomplete\nconntrack state.",
  "id": "GHSA-hh4g-5q85-w496",
  "modified": "2026-08-15T06:32:17Z",
  "published": "2026-08-15T06:32:17Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-72256"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/07f9ddbf5e799c24a3a52ec9bd7b729a6f6d69d5"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/13ea4f86cf738c74be2146886ac261988a631e62"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/4558bd7b47c7be82dffd837f27be8ea3ecee557d"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/4cb8b5f586e41c187942291cc0938006077fa79e"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/5b2d4f0010018a7aa3495aa1dbf1b7a34011e7aa"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/5feba91006ec92da57acc1cc2e34df623b98541e"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/d5f9d050b0b267227c1f02f11021872c7768a9cc"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/fac2fdac3baad9ffd12b3b0bba4374d4b3585d54"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}



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