Vulnerability-Lookup

GHSA-4WGJ-9QHP-2583

Vulnerability from github – Published: 2026-08-28 09:31 – Updated: 2026-08-29 09:30

Details

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

netfilter: xt_nat: reject unsupported target families

xt_nat SNAT and DNAT target handlers assume IP-family conntrack state is present and can dereference a NULL pointer when instantiated from an unsupported family through nft_compat. A bridge-family compat rule can therefore trigger a NULL-dereference in nf_nat_setup_info().

Reject non-IP families in xt_nat_checkentry() so unsupported targets cannot be installed. Keep NFPROTO_INET allowed for valid inet NAT compat users and leave the runtime fast path unchanged.

[ The crash was fixed via 9dbba7e694ec ("netfilter: nft_compat: ebtables emulation must reject non-bridge targets"), so this patch is no longer critical. Nevertheless, NAT is only relevant for ipv4/ipv6, so this extra family check is a good idea in any case. ]

Severity

7.3 (High)


                  
                    CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:H

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{
  "affected": [],
  "aliases": [
    "CVE-2026-80664"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-08-28T08:16:51Z",
    "severity": "HIGH"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: xt_nat: reject unsupported target families\n\nxt_nat SNAT and DNAT target handlers assume IP-family conntrack state\nis present and can dereference a NULL pointer when instantiated from an\nunsupported family through nft_compat. A bridge-family compat rule can\ntherefore trigger a NULL-dereference in nf_nat_setup_info().\n\nReject non-IP families in xt_nat_checkentry() so unsupported targets\ncannot be installed. Keep NFPROTO_INET allowed for valid inet NAT\ncompat users and leave the runtime fast path unchanged.\n\n[ The crash was fixed via\n  9dbba7e694ec (\"netfilter: nft_compat: ebtables emulation must reject non-bridge targets\"),\n  so this patch is no longer critical.\n  Nevertheless, NAT is only relevant for ipv4/ipv6, so this extra\n  family check is a good idea in any case. ]",
  "id": "GHSA-4wgj-9qhp-2583",
  "modified": "2026-08-29T09:30:27Z",
  "published": "2026-08-28T09:31:48Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-80664"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/0afc9ad987c0faa80ab5f8d6e7815085ac8dbb82"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/49abe564391411057a26a9a943c8e17867c3b9b4"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/4fbc2bac02edabb665beb2aa87ca6f1e1d4c4777"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/5d1a2240935ea47e2673d0ea17fdb058e4dc91dd"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/679ced28a9dc2f6dc679eb05027d779693e60902"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/a842dab87cab29f2a5798a47b2dc5e6a449950bf"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/e35c048d7511e9d4c2a537b8a231c49606e97c16"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/ec88fa71c82072e9189983b05b499d3507550271"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}

CVE-2026-80664 (GCVE-0-2026-80664)

Vulnerability from cvelistv5 – Published: 2026-08-28 06:49 – Updated: 2026-08-29 06:21

Title

netfilter: xt_nat: reject unsupported target families

Summary

In the Linux kernel, the following vulnerability has been resolved: netfilter: xt_nat: reject unsupported target families xt_nat SNAT and DNAT target handlers assume IP-family conntrack state is present and can dereference a NULL pointer when instantiated from an unsupported family through nft_compat. A bridge-family compat rule can therefore trigger a NULL-dereference in nf_nat_setup_info(). Reject non-IP families in xt_nat_checkentry() so unsupported targets cannot be installed. Keep NFPROTO_INET allowed for valid inet NAT compat users and leave the runtime fast path unchanged. [ The crash was fixed via 9dbba7e694ec ("netfilter: nft_compat: ebtables emulation must reject non-bridge targets"), so this patch is no longer critical. Nevertheless, NAT is only relevant for ipv4/ipv6, so this extra family check is a good idea in any case. ]

Severity

7.3 (High)


                        
                          CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:H

Assigner

Linux mitre root

References

8 references

URL	Tags
https://git.kernel.org/stable/c/49abe564391411057…
https://git.kernel.org/stable/c/0afc9ad987c0faa80…
https://git.kernel.org/stable/c/4fbc2bac02edabb66…
https://git.kernel.org/stable/c/a842dab87cab29f2a…
https://git.kernel.org/stable/c/e35c048d7511e9d4c…
https://git.kernel.org/stable/c/679ced28a9dc2f6dc…
https://git.kernel.org/stable/c/ec88fa71c82072e91…
https://git.kernel.org/stable/c/5d1a2240935ea47e2…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: c7232c9979cba684c50b64c513c4a83c9aa70563 , < 49abe564391411057a26a9a943c8e17867c3b9b4 (git) Affected: c7232c9979cba684c50b64c513c4a83c9aa70563 , < 0afc9ad987c0faa80ab5f8d6e7815085ac8dbb82 (git) Affected: c7232c9979cba684c50b64c513c4a83c9aa70563 , < 4fbc2bac02edabb665beb2aa87ca6f1e1d4c4777 (git) Affected: c7232c9979cba684c50b64c513c4a83c9aa70563 , < a842dab87cab29f2a5798a47b2dc5e6a449950bf (git) Affected: c7232c9979cba684c50b64c513c4a83c9aa70563 , < e35c048d7511e9d4c2a537b8a231c49606e97c16 (git) Affected: c7232c9979cba684c50b64c513c4a83c9aa70563 , < 679ced28a9dc2f6dc679eb05027d779693e60902 (git) Affected: c7232c9979cba684c50b64c513c4a83c9aa70563 , < ec88fa71c82072e9189983b05b499d3507550271 (git) Affected: c7232c9979cba684c50b64c513c4a83c9aa70563 , < 5d1a2240935ea47e2673d0ea17fdb058e4dc91dd (git)
Linux	Linux	Affected: 3.7 Unaffected: 0 , < 3.7 (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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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/netfilter/xt_nat.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "49abe564391411057a26a9a943c8e17867c3b9b4",
              "status": "affected",
              "version": "c7232c9979cba684c50b64c513c4a83c9aa70563",
              "versionType": "git"
            },
            {
              "lessThan": "0afc9ad987c0faa80ab5f8d6e7815085ac8dbb82",
              "status": "affected",
              "version": "c7232c9979cba684c50b64c513c4a83c9aa70563",
              "versionType": "git"
            },
            {
              "lessThan": "4fbc2bac02edabb665beb2aa87ca6f1e1d4c4777",
              "status": "affected",
              "version": "c7232c9979cba684c50b64c513c4a83c9aa70563",
              "versionType": "git"
            },
            {
              "lessThan": "a842dab87cab29f2a5798a47b2dc5e6a449950bf",
              "status": "affected",
              "version": "c7232c9979cba684c50b64c513c4a83c9aa70563",
              "versionType": "git"
            },
            {
              "lessThan": "e35c048d7511e9d4c2a537b8a231c49606e97c16",
              "status": "affected",
              "version": "c7232c9979cba684c50b64c513c4a83c9aa70563",
              "versionType": "git"
            },
            {
              "lessThan": "679ced28a9dc2f6dc679eb05027d779693e60902",
              "status": "affected",
              "version": "c7232c9979cba684c50b64c513c4a83c9aa70563",
              "versionType": "git"
            },
            {
              "lessThan": "ec88fa71c82072e9189983b05b499d3507550271",
              "status": "affected",
              "version": "c7232c9979cba684c50b64c513c4a83c9aa70563",
              "versionType": "git"
            },
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              "status": "affected",
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              "versionType": "git"
            }
          ]
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        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
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          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "3.7"
            },
            {
              "lessThan": "3.7",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.261",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.212",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.178",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.145",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.97",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.40",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.5",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
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            {
              "cpeMatch": [
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                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.10.261",
                  "versionStartIncluding": "3.7",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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                  "versionStartIncluding": "3.7",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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                  "versionStartIncluding": "3.7",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.40",
                  "versionStartIncluding": "3.7",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.1.5",
                  "versionStartIncluding": "3.7",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2",
                  "versionStartIncluding": "3.7",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: xt_nat: reject unsupported target families\n\nxt_nat SNAT and DNAT target handlers assume IP-family conntrack state\nis present and can dereference a NULL pointer when instantiated from an\nunsupported family through nft_compat. A bridge-family compat rule can\ntherefore trigger a NULL-dereference in nf_nat_setup_info().\n\nReject non-IP families in xt_nat_checkentry() so unsupported targets\ncannot be installed. Keep NFPROTO_INET allowed for valid inet NAT\ncompat users and leave the runtime fast path unchanged.\n\n[ The crash was fixed via\n  9dbba7e694ec (\"netfilter: nft_compat: ebtables emulation must reject non-bridge targets\"),\n  so this patch is no longer critical.\n  Nevertheless, NAT is only relevant for ipv4/ipv6, so this extra\n  family check is a good idea in any case. ]"
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.3,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - Exploitation requires installing a bridge-family nft_compat SNAT/DNAT rule via NETLINK_NETFILTER (nftables netlink), a local syscall path; although matching bridge traffic can trigger evaluation, the vulnerable rule state cannot be created without local netfilter administration.\nAC:L - Once CAP_NET_ADMIN is held in the target network namespace, xt_request_find_target() deterministically resolves UNSPEC-family SNAT/DNAT rev 1/2 targets for bridge chains, and sending bridge traffic through the committed rule reliably reaches nf_nat_setup_info() with a NULL nf_conn from nf_ct_get().\nPR:L - All nfnetlink handlers are gated by netlink_net_capable(skb, CAP_NET_ADMIN), which checks capability in the socket network namespace user namespace; unprivileged local users routinely obtain CAP_NET_ADMIN via user and network namespaces (unshare -Urn), enabling installation of the malicious bridge compat rule.\nUI:N - No victim interaction is required beyond the attacker obtaining namespace-local CAP_NET_ADMIN, creating a bridge nftables chain with a compat SNAT/DNAT target, and delivering matching bridge traffic; no third-party actions such as mounting filesystems or opening files are needed.\nS:U - Impact is confined to the host kernel netfilter/NAT subsystem within the same security authority; this is not a VM escape, hypervisor boundary crossing, or IOMMU/DMA sandbox bypass, but standard in-kernel misbehavior from an invalid family/target pairing.\nC:L - The primary runtime failure is a NULL nf_conn dereference in nf_nat_setup_info(), and the surrounding nft_compat bridge/xtables semantic mismatch can leak limited kernel information via oops register dumps and crash logs readable by the local attacker who triggered the fault.\nI:H - Missing family validation lets IP-family NAT targets execute under bridge nft_compat semantics where nf_ct_get() yields NULL, constituting a type/family confusion that can corrupt netfilter verdict and NAT handling before faulting; mis-instantiated SNAT/DNAT targets should not run in bridge context at all.\nA:H - Passing bridge traffic through a bridge-family compat SNAT/DNAT rule causes nf_nat_setup_info() to dereference the NULL connection from nf_ct_get(), producing a kernel oops or panic; repeated matching traffic can retrigger the crash for sustained denial of service."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-29T06:21:50.580Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
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        },
        {
          "url": "https://git.kernel.org/stable/c/679ced28a9dc2f6dc679eb05027d779693e60902"
        },
        {
          "url": "https://git.kernel.org/stable/c/ec88fa71c82072e9189983b05b499d3507550271"
        },
        {
          "url": "https://git.kernel.org/stable/c/5d1a2240935ea47e2673d0ea17fdb058e4dc91dd"
        }
      ],
      "title": "netfilter: xt_nat: reject unsupported target families",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-80664",
    "datePublished": "2026-08-28T06:49:07.478Z",
    "dateReserved": "2026-08-26T14:34:25.781Z",
    "dateUpdated": "2026-08-29T06:21:50.580Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

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.

Action not permitted

GHSA-4WGJ-9QHP-2583

CVE-2026-80664 (GCVE-0-2026-80664)

Tags

Sightings

Nomenclature