CVE-2026-98568 (GCVE-0-2026-98568)

Vulnerability from cvelistv5 – Published: 2026-10-18 15:18 – Updated: 2026-10-30 12:38
VLAI
Title
vxlan: use one headroom snapshot for neighbour replies
Summary
In the Linux kernel, the following vulnerability has been resolved: vxlan: use one headroom snapshot for neighbour replies vxlan_na_create() samples LL_RESERVED_SPACE() to size the reply skb and then samples it again to reserve headroom. A concurrent vxlan_changelink() can update needed_headroom between the two reads, creating a TOCTOU race. The second value can exceed the allocation and make the Ethernet header write out of bounds. The race is reproducible on the unpatched kernel. It occurred when vxlan_na_create() generated a neighbour reply while vxlan_changelink() changed the link headroom. KASAN caught a four-byte write two bytes beyond a 704-byte skbuff_small_head allocation. Snapshot the headroom once and use that value for both allocation and reservation.
Severity
No CVSS data available.
Assigner
Linux CNA under the mitre root
CNA scorecard D 53/100 over 7018 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 4b29dba9c085a4fb79058fb1c45a2f6257ca3dfa , < e3e24f4c434c56952412f875b834aa9daaa4fb15 (git)
Affected: 4b29dba9c085a4fb79058fb1c45a2f6257ca3dfa , < 9ed5a548b42d46e6968a46b67ca8a8e49b12a5a1 (git)
Affected: 4b29dba9c085a4fb79058fb1c45a2f6257ca3dfa , < fcaf456092dc86fd5b0b523ac27ec0d114066931 (git)
Affected: 4b29dba9c085a4fb79058fb1c45a2f6257ca3dfa , < 45a67662bf8ce3aa5643accf98d328dfbb47eaf6 (git)
Affected: 4b29dba9c085a4fb79058fb1c45a2f6257ca3dfa , < 315d42ca39f69846662961c25dcf2bb07c350d14 (git)
Affected: 4b29dba9c085a4fb79058fb1c45a2f6257ca3dfa , < a3c5eb6e382dd426a5e7eb08608897ed57167ff7 (git)
Affected: 4b29dba9c085a4fb79058fb1c45a2f6257ca3dfa , < ff022fd9d0f0282c575e11778b96bd1b637503eb (git)
Affected: 4b29dba9c085a4fb79058fb1c45a2f6257ca3dfa , < 481506a756dcd828ef42391cb08f38d8d96d38fc (git)
Affected: d8be18c52dbc94989f6d74637b731af39cd3d902 (git)
Affected: 3927dace523706cc00f808520eaf2125dd7c07b5 (git)
Affected: 3.12.18 , < 3.13 (semver)
Affected: 3.13.10 , < 3.14 (semver)
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Linux Linux Affected: 3.14
Unaffected: 0 , < 3.14 (semver)
Unaffected: 5.10.273 , ≤ 5.10.* (semver)
Unaffected: 5.15.224 , ≤ 5.15.* (semver)
Unaffected: 6.1.191 , ≤ 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)
guessed Create a notification for this product.
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        {
          "url": "https://git.kernel.org/stable/c/481506a756dcd828ef42391cb08f38d8d96d38fc"
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            "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nvxlan: use one headroom snapshot for neighbour replies\n\nvxlan_na_create() samples LL_RESERVED_SPACE() to size the reply skb and then\nsamples it again to reserve headroom. A concurrent vxlan_changelink() can\nupdate needed_headroom between the two reads, creating a TOCTOU race. The\nsecond value can exceed the allocation and make the Ethernet header write out\nof bounds.\n\nThe race is reproducible on the unpatched kernel. It occurred when\nvxlan_na_create() generated a neighbour reply while vxlan_changelink() changed\nthe link headroom. KASAN caught a four-byte write two bytes beyond a 704-byte\nskbuff_small_head allocation.\n\nSnapshot the headroom once and use that value for both allocation and\nreservation."
          }
        ],
        "id": "CVE-2026-98568",
        "lastModified": "2026-10-30T13:21:16.090",
        "metrics": {},
        "published": "2026-10-18T16:17:09.000",
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        "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "vulnStatus": "Received"
      }
    },
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      "aggregate_severity": "Moderate",
      "current_release_date": "2026-10-30T07:02:58+00:00",
      "cve": "CVE-2026-98568",
      "id": "CVE-2026-98568",
      "initial_release_date": "2026-10-18T00:00:00+00:00",
      "product_status:known_affected": "188",
      "product_status:known_not_affected": "91",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: vxlan: use one headroom snapshot for neighbour replies",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-98568.json",
      "version": "3"
    }
  }
}



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Tags
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.