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CVE-2026-72256 (GCVE-0-2026-72256)

Vulnerability from cvelistv5 – Published: 2026-08-15 05:54 – Updated: 2026-08-17 05:11
VLAI
Title
netfilter: xt_cluster: reject template conntracks in hash match
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.
Severity
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 0269ea4937343536ec7e85649932bc8c9686ea78 , < 4558bd7b47c7be82dffd837f27be8ea3ecee557d (git)
Affected: 0269ea4937343536ec7e85649932bc8c9686ea78 , < d5f9d050b0b267227c1f02f11021872c7768a9cc (git)
Affected: 0269ea4937343536ec7e85649932bc8c9686ea78 , < 4cb8b5f586e41c187942291cc0938006077fa79e (git)
Affected: 0269ea4937343536ec7e85649932bc8c9686ea78 , < fac2fdac3baad9ffd12b3b0bba4374d4b3585d54 (git)
Affected: 0269ea4937343536ec7e85649932bc8c9686ea78 , < 13ea4f86cf738c74be2146886ac261988a631e62 (git)
Affected: 0269ea4937343536ec7e85649932bc8c9686ea78 , < 07f9ddbf5e799c24a3a52ec9bd7b729a6f6d69d5 (git)
Affected: 0269ea4937343536ec7e85649932bc8c9686ea78 , < 5b2d4f0010018a7aa3495aa1dbf1b7a34011e7aa (git)
Affected: 0269ea4937343536ec7e85649932bc8c9686ea78 , < 5feba91006ec92da57acc1cc2e34df623b98541e (git)
guessed Create a notification for this product.
Linux Linux Affected: 2.6.30
Unaffected: 0 , < 2.6.30 (semver)
Unaffected: 5.10.261 , ≤ 5.10.* (semver)
Unaffected: 5.15.212 , ≤ 5.15.* (semver)
Unaffected: 6.1.178 , ≤ 6.1.* (semver)
Unaffected: 6.6.145 , ≤ 6.6.* (semver)
Unaffected: 6.12.97 , ≤ 6.12.* (semver)
Unaffected: 6.18.40 , ≤ 6.18.* (semver)
Unaffected: 7.1.5 , ≤ 7.1.* (semver)
Unaffected: 7.2 , ≤ * (original_commit_for_fix)
guessed Create a notification for this product.
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    "datePublished": "2026-08-15T05:54:43.706Z",
    "dateReserved": "2026-08-09T03:40:39.915Z",
    "dateUpdated": "2026-08-17T05:11:14.683Z",
    "state": "PUBLISHED"
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    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-08-18T18:29:19+00:00",
      "cve": "CVE-2026-72256",
      "id": "CVE-2026-72256",
      "initial_release_date": "2026-08-15T00:00:00+00:00",
      "product_status:known_affected": "274",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: netfilter: xt_cluster: reject template conntracks in hash match",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-72256.json",
      "version": "3"
    }
  }
}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

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Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
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  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
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Detection rules are retrieved from Rulezet.