CVE-2026-80636 (GCVE-0-2026-80636)

Vulnerability from cvelistv5 – Published: 2026-08-28 06:48 – Updated: 2026-08-28 06:48
VLAI
Title
netfilter: conntrack: revert ct extension genid infrastructure
Summary
In the Linux kernel, the following vulnerability has been resolved: netfilter: conntrack: revert ct extension genid infrastructure This infrastructure is not used anymore after moving ct timeout and helper to use datapath refcount to track object use. Revert commit c56716c69ce1 ("netfilter: extensions: introduce extension genid count") this patch disables all ct extensions (leading to NULL) for unconfirmed conntracks, when this is only targeted at ct helper and ct timeout. There is also codebase that dereferences the ct extension without checking for NULL which could lead to crash.
Severity
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: c56716c69ce1ac320432fb1ea5654196ba24d2f8 , < 6bba4846f196d081bf553391d12b5a73dcc48685 (git)
Affected: c56716c69ce1ac320432fb1ea5654196ba24d2f8 , < 61eab1d0237eb513fe73e391a5926ee70092c325 (git)
Affected: c56716c69ce1ac320432fb1ea5654196ba24d2f8 , < d53eecbca16f056abba274075cb15120ab062518 (git)
Affected: c56716c69ce1ac320432fb1ea5654196ba24d2f8 , < a052a94bcc629acaecc2ce42a4af77f8fa399757 (git)
Affected: c56716c69ce1ac320432fb1ea5654196ba24d2f8 , < 35e21a4dccc5c255ba59ccfbfeb4629ed21da972 (git)
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Linux Linux Affected: 5.19
Unaffected: 0 , < 5.19 (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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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "include/net/netfilter/nf_conntrack_extend.h",
            "net/netfilter/nf_conntrack_core.c",
            "net/netfilter/nf_conntrack_extend.c"
          ],
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              "status": "unaffected",
              "version": "6.18.40",
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              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
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              "negate": false,
              "operator": "OR"
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      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: conntrack: revert ct extension genid infrastructure\n\nThis infrastructure is not used anymore after moving ct timeout and\nhelper to use datapath refcount to track object use.\n\nRevert commit c56716c69ce1 (\"netfilter: extensions: introduce extension\ngenid count\") this patch disables all ct extensions (leading to NULL)\nfor unconfirmed conntracks, when this is only targeted at ct helper and\nct timeout. There is also codebase that dereferences the ct extension\nwithout checking for NULL which could lead to crash."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-28T06:48:50.241Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/6bba4846f196d081bf553391d12b5a73dcc48685"
        },
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        },
        {
          "url": "https://git.kernel.org/stable/c/d53eecbca16f056abba274075cb15120ab062518"
        },
        {
          "url": "https://git.kernel.org/stable/c/a052a94bcc629acaecc2ce42a4af77f8fa399757"
        },
        {
          "url": "https://git.kernel.org/stable/c/35e21a4dccc5c255ba59ccfbfeb4629ed21da972"
        }
      ],
      "title": "netfilter: conntrack: revert ct extension genid infrastructure",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
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  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-80636",
    "datePublished": "2026-08-28T06:48:50.241Z",
    "dateReserved": "2026-08-26T14:34:25.777Z",
    "dateUpdated": "2026-08-28T06:48:50.241Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
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      "date": "2026-09-01",
      "epss": "0.00168",
      "percentile": "0.06288"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-80636\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2026-08-28T08:16:48.513\",\"lastModified\":\"2026-08-28T08:16:48.513\",\"vulnStatus\":\"Received\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"In the Linux kernel, the following vulnerability has been resolved:\\n\\nnetfilter: conntrack: revert ct extension genid infrastructure\\n\\nThis infrastructure is not used anymore after moving ct timeout and\\nhelper to use datapath refcount to track object use.\\n\\nRevert commit c56716c69ce1 (\\\"netfilter: extensions: introduce extension\\ngenid count\\\") this patch disables all ct extensions (leading to NULL)\\nfor unconfirmed conntracks, when this is only targeted at ct helper and\\nct timeout. There is also codebase that dereferences the ct extension\\nwithout checking for NULL which could lead to crash.\"}],\"affected\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"affectedData\":[{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"unaffected\",\"programFiles\":[\"include/net/netfilter/nf_conntrack_extend.h\",\"net/netfilter/nf_conntrack_core.c\",\"net/netfilter/nf_conntrack_extend.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"c56716c69ce1ac320432fb1ea5654196ba24d2f8\",\"lessThan\":\"6bba4846f196d081bf553391d12b5a73dcc48685\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"c56716c69ce1ac320432fb1ea5654196ba24d2f8\",\"lessThan\":\"61eab1d0237eb513fe73e391a5926ee70092c325\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"c56716c69ce1ac320432fb1ea5654196ba24d2f8\",\"lessThan\":\"d53eecbca16f056abba274075cb15120ab062518\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"c56716c69ce1ac320432fb1ea5654196ba24d2f8\",\"lessThan\":\"a052a94bcc629acaecc2ce42a4af77f8fa399757\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"c56716c69ce1ac320432fb1ea5654196ba24d2f8\",\"lessThan\":\"35e21a4dccc5c255ba59ccfbfeb4629ed21da972\",\"versionType\":\"git\",\"status\":\"affected\"}]},{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"affected\",\"programFiles\":[\"include/net/netfilter/nf_conntrack_extend.h\",\"net/netfilter/nf_conntrack_core.c\",\"net/netfilter/nf_conntrack_extend.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"5.19\",\"status\":\"affected\"},{\"version\":\"0\",\"lessThan\":\"5.19\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.6.145\",\"lessThanOrEqual\":\"6.6.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.12.97\",\"lessThanOrEqual\":\"6.12.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.18.40\",\"lessThanOrEqual\":\"6.18.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.1.5\",\"lessThanOrEqual\":\"7.1.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.2\",\"lessThanOrEqual\":\"*\",\"versionType\":\"original_commit_for_fix\",\"status\":\"unaffected\"}]}]}],\"metrics\":{},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/35e21a4dccc5c255ba59ccfbfeb4629ed21da972\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/61eab1d0237eb513fe73e391a5926ee70092c325\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/6bba4846f196d081bf553391d12b5a73dcc48685\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/a052a94bcc629acaecc2ce42a4af77f8fa399757\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/d53eecbca16f056abba274075cb15120ab062518\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}",
    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-08-31T09:47:08+00:00",
      "cve": "CVE-2026-80636",
      "id": "CVE-2026-80636",
      "initial_release_date": "2026-08-28T00:00:00+00:00",
      "product_status:known_affected": "198",
      "product_status:known_not_affected": "76",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: netfilter: conntrack: revert ct extension genid infrastructure",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-80636.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.
  • 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.