CVE-2026-98554 (GCVE-0-2026-98554)

Vulnerability from cvelistv5 – Published: 2026-10-18 15:18 – Updated: 2026-10-19 09:21
VLAI
Title
vlan: ensure sufficient headroom in vlan_dev_hard_header()
Summary
In the Linux kernel, the following vulnerability has been resolved: vlan: ensure sufficient headroom in vlan_dev_hard_header() Callers that only reserve ETH_HLEN or less (such as llc_alloc_frame()), or skbs allocated before dynamic device/headroom changes (e.g. toggling VLAN_FLAG_REORDER_HDR or bonding/team switching slaves), can reach vlan_dev_hard_header() with insufficient headroom and trigger skb_under_panic(). Use skb_cow_head() in vlan_dev_hard_header() when VLAN_FLAG_REORDER_HDR is not set to ensure sufficient headroom for the VLAN header(s) and the underlying device hard header. Use READ_ONCE() to read dev->hard_header_len and dev->needed_headroom as they can be updated concurrently under RTNL (e.g. in vlan_transfer_features()) while vlan_dev_hard_header() runs locklessly on the transmit path. Also avoid LL_RESERVED_SPACE(dev) here so that the extra HH_DATA_MOD alignment padding does not trigger unnecessary pskb_expand_head() reallocations on inner stacked VLAN devices after the outer VLAN header has been pushed.
Severity
No CVSS data available.
Assigner
Linux CNA under the mitre root
CNA scorecard D 53/100 over 6843 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 55e007fc3b4d76fa4d6b4660f6904fe6ab045a1b (git)
Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 5aca8e6a8ff6aeae358c1d9b65447aac416ace95 (git)
Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 4ba1f57313f36a3ce6f77d593548f0c511f34aa1 (git)
Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < ca797491f0ae4bfde9039f79f6f1ed7781c9110f (git)
Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < cfba0f45553de2b803059e3d539a1e418df24da8 (git)
Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < c7ee4bea64f559ea8e03260014775b64c720cb5b (git)
Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 90d51095371d96747f45bbd8504edf6513e039ef (git)
Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < cd5dd68267c4238795fadaf02b3575ca3f8a6500 (git)
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Linux Linux Affected: 2.6.12
Unaffected: 0 , < 2.6.12 (semver)
Unaffected: 5.10.271 , ≤ 5.10.* (semver)
Unaffected: 5.15.222 , ≤ 5.15.* (semver)
Unaffected: 6.1.189 , ≤ 6.1.* (semver)
Unaffected: 6.6.158 , ≤ 6.6.* (semver)
Unaffected: 6.12.112 , ≤ 6.12.* (semver)
Unaffected: 6.18.55 , ≤ 6.18.* (semver)
Unaffected: 7.2.9 , ≤ 7.2.* (semver)
Unaffected: 7.3 , ≤ * (original_commit_for_fix)
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{
  "containers": {
    "cna": {
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        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/8021q/vlan_dev.c"
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              "version": "7.3",
              "versionType": "original_commit_for_fix"
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      ],
      "cpeApplicability": [
        {
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              "operator": "OR"
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      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nvlan: ensure sufficient headroom in vlan_dev_hard_header()\n\nCallers that only reserve ETH_HLEN or less (such as llc_alloc_frame()),\nor skbs allocated before dynamic device/headroom changes (e.g. toggling\nVLAN_FLAG_REORDER_HDR or bonding/team switching slaves), can reach\nvlan_dev_hard_header() with insufficient headroom and trigger\nskb_under_panic().\n\nUse skb_cow_head() in vlan_dev_hard_header() when VLAN_FLAG_REORDER_HDR\nis not set to ensure sufficient headroom for the VLAN header(s) and the\nunderlying device hard header.\n\nUse READ_ONCE() to read dev-\u003ehard_header_len and dev-\u003eneeded_headroom as\nthey can be updated concurrently under RTNL (e.g. in\nvlan_transfer_features()) while vlan_dev_hard_header() runs locklessly on\nthe transmit path. Also avoid LL_RESERVED_SPACE(dev) here so that the\nextra HH_DATA_MOD alignment padding does not trigger unnecessary\npskb_expand_head() reallocations on inner stacked VLAN devices after the\nouter VLAN header has been pushed."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-19T09:21:37.221Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
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          "url": "https://git.kernel.org/stable/c/55e007fc3b4d76fa4d6b4660f6904fe6ab045a1b"
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          "url": "https://git.kernel.org/stable/c/5aca8e6a8ff6aeae358c1d9b65447aac416ace95"
        },
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          "url": "https://git.kernel.org/stable/c/4ba1f57313f36a3ce6f77d593548f0c511f34aa1"
        },
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        {
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        },
        {
          "url": "https://git.kernel.org/stable/c/cd5dd68267c4238795fadaf02b3575ca3f8a6500"
        }
      ],
      "title": "vlan: ensure sufficient headroom in vlan_dev_hard_header()",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
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    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-98554",
    "datePublished": "2026-10-18T15:18:21.751Z",
    "dateReserved": "2026-09-25T10:25:14.356Z",
    "dateUpdated": "2026-10-19T09:21:37.221Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
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      "date": "2026-10-22",
      "epss": "0.0021",
      "percentile": "0.1071"
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    "microsoft_vex": {
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      "id": "msrc_CVE-2026-98554",
      "initial_release_date": "2026-10-20T01:09:43.000Z",
      "product_status:known_affected": "1",
      "product_status:under_investigation": "1",
      "source": "Microsoft CSAF VEX",
      "status": "final",
      "title": "vlan: ensure sufficient headroom in vlan_dev_hard_header()",
      "url": "https://msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-98554.json",
      "version": "3"
    },
    "nvd": {
      "cve": {
        "affected": [
          {
            "affectedData": [
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                "product": "Linux",
                "programFiles": [
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                "vendor": "Linux",
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            ],
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
          }
        ],
        "cveTags": [],
        "descriptions": [
          {
            "lang": "en",
            "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nvlan: ensure sufficient headroom in vlan_dev_hard_header()\n\nCallers that only reserve ETH_HLEN or less (such as llc_alloc_frame()),\nor skbs allocated before dynamic device/headroom changes (e.g. toggling\nVLAN_FLAG_REORDER_HDR or bonding/team switching slaves), can reach\nvlan_dev_hard_header() with insufficient headroom and trigger\nskb_under_panic().\n\nUse skb_cow_head() in vlan_dev_hard_header() when VLAN_FLAG_REORDER_HDR\nis not set to ensure sufficient headroom for the VLAN header(s) and the\nunderlying device hard header.\n\nUse READ_ONCE() to read dev-\u003ehard_header_len and dev-\u003eneeded_headroom as\nthey can be updated concurrently under RTNL (e.g. in\nvlan_transfer_features()) while vlan_dev_hard_header() runs locklessly on\nthe transmit path. Also avoid LL_RESERVED_SPACE(dev) here so that the\nextra HH_DATA_MOD alignment padding does not trigger unnecessary\npskb_expand_head() reallocations on inner stacked VLAN devices after the\nouter VLAN header has been pushed."
          }
        ],
        "id": "CVE-2026-98554",
        "lastModified": "2026-10-19T10:19:11.773",
        "metrics": {},
        "published": "2026-10-18T16:17:07.490",
        "references": [
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/90d51095371d96747f45bbd8504edf6513e039ef"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/c7ee4bea64f559ea8e03260014775b64c720cb5b"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/ca797491f0ae4bfde9039f79f6f1ed7781c9110f"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/cd5dd68267c4238795fadaf02b3575ca3f8a6500"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/cfba0f45553de2b803059e3d539a1e418df24da8"
          }
        ],
        "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "vulnStatus": "Received"
      }
    },
    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-10-20T01:30:04+00:00",
      "cve": "CVE-2026-98554",
      "id": "CVE-2026-98554",
      "initial_release_date": "2026-10-18T00:00:00+00:00",
      "product_status:known_affected": "277",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: vlan: ensure sufficient headroom in vlan_dev_hard_header()",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-98554.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "moderate",
      "current_release_date": "2026-10-22T16:36:56Z",
      "cve": "CVE-2026-98554",
      "id": "CVE-2026-98554",
      "initial_release_date": "2026-10-22T16:36:56Z",
      "product_status:known_affected": "344",
      "product_status:known_not_affected": "4",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-98554",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/2026/cve-2026-98554.json",
      "version": "2"
    }
  }
}



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Taxonomy of the tags.




Drag nodes to arrange them. Double-click a related vulnerability to open it, or a source to visit its link. The Physics button on the left tunes the layout and the simulation; the legend at the bottom left hides or shows nodes by kind and by sighting type.

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

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.
Vulnerability timeline

Sightings and recorded dates, grouped by day · UTC

JSON

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    Related by attack behaviour

    Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.