Vulnerability-Lookup

GHSA-HH4G-5Q85-W496

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

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": []
}

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

Vulnerability from cvelistv5 – Published: 2026-08-15 05:54 – Updated: 2026-08-17 05:11

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

Linux mitre root

References

8 references

URL	Tags
https://git.kernel.org/stable/c/4558bd7b47c7be82d…
https://git.kernel.org/stable/c/d5f9d050b0b267227…
https://git.kernel.org/stable/c/4cb8b5f586e41c187…
https://git.kernel.org/stable/c/fac2fdac3baad9ffd…
https://git.kernel.org/stable/c/13ea4f86cf738c74b…
https://git.kernel.org/stable/c/07f9ddbf5e799c24a…
https://git.kernel.org/stable/c/5b2d4f0010018a7aa…
https://git.kernel.org/stable/c/5feba91006ec92da5…

Impacted products

2 products

Vendor	Product	Version
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)
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)

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Sightings

Author	Source	Type	Date	Other

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.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
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.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.

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GHSA-HH4G-5Q85-W496

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

Tags

Sightings

Nomenclature