CVE-2026-72256 (GCVE-0-2026-72256)
Vulnerability from cvelistv5
Published
2026-08-15 05:54
Modified
2026-08-17 05:11
Severity ?
Summary
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.
References
Impacted products
Vendor Product Version
Linux Linux Version: 0269ea4937343536ec7e85649932bc8c9686ea78
Version: 0269ea4937343536ec7e85649932bc8c9686ea78
Version: 0269ea4937343536ec7e85649932bc8c9686ea78
Version: 0269ea4937343536ec7e85649932bc8c9686ea78
Version: 0269ea4937343536ec7e85649932bc8c9686ea78
Version: 0269ea4937343536ec7e85649932bc8c9686ea78
Version: 0269ea4937343536ec7e85649932bc8c9686ea78
Version: 0269ea4937343536ec7e85649932bc8c9686ea78
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{
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      "cpeApplicability": [
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      "descriptions": [
        {
          "lang": "en",
          "value": "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."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-17T05:11:14.683Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
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          "url": "https://git.kernel.org/stable/c/4558bd7b47c7be82dffd837f27be8ea3ecee557d"
        },
        {
          "url": "https://git.kernel.org/stable/c/d5f9d050b0b267227c1f02f11021872c7768a9cc"
        },
        {
          "url": "https://git.kernel.org/stable/c/4cb8b5f586e41c187942291cc0938006077fa79e"
        },
        {
          "url": "https://git.kernel.org/stable/c/fac2fdac3baad9ffd12b3b0bba4374d4b3585d54"
        },
        {
          "url": "https://git.kernel.org/stable/c/13ea4f86cf738c74be2146886ac261988a631e62"
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          "url": "https://git.kernel.org/stable/c/5b2d4f0010018a7aa3495aa1dbf1b7a34011e7aa"
        },
        {
          "url": "https://git.kernel.org/stable/c/5feba91006ec92da57acc1cc2e34df623b98541e"
        }
      ],
      "title": "netfilter: xt_cluster: reject template conntracks in hash match",
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  "cveMetadata": {
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    "assignerShortName": "Linux",
    "cveId": "CVE-2026-72256",
    "datePublished": "2026-08-15T05:54:43.706Z",
    "dateReserved": "2026-08-09T03:40:39.915Z",
    "dateUpdated": "2026-08-17T05:11:14.683Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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