Vulnerability-Lookup

GHSA-M243-8CM2-374C

Vulnerability from github – Published: 2026-08-10 15:33 – Updated: 2026-08-19 18:32

Details

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

vmxnet3: fix BUG_ON in vmxnet3_get_hdr_len() for Geneve packets

vmxnet3_get_hdr_len() assumes gdesc->rcd.v4/v6/tcp always describe the outer header, but for a Geneve-encapsulated packet the device can set them based on the inner header instead, signalled by the VMXNET3_RCD_HDR_INNER_SHIFT bit in the completion descriptor. Since the function never skips the outer encapsulation, this mismatch triggers:

BUG_ON(hdr.ipv4->protocol != IPPROTO_TCP), because the outer protocol is UDP (Geneve), not TCP.
BUG_ON(hdr.eth->h_proto != ...), when the tunnel's outer and inner IP versions differ (e.g. outer IPv6/inner IPv4 or vice versa).

Check VMXNET3_RCD_HDR_INNER_SHIFT up front and bail out, since the function cannot locate the inner header it would need to parse. Also convert the remaining BUG_ON()s in this function to return 0 defensively.

Severity

7.5 (High)


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

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{
  "affected": [],
  "aliases": [
    "CVE-2026-68299"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-08-10T13:20:19Z",
    "severity": "HIGH"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nvmxnet3: fix BUG_ON in vmxnet3_get_hdr_len() for Geneve packets\n\nvmxnet3_get_hdr_len() assumes gdesc-\u003ercd.v4/v6/tcp always describe the\nouter header, but for a Geneve-encapsulated packet the device can set\nthem based on the inner header instead, signalled by the\nVMXNET3_RCD_HDR_INNER_SHIFT bit in the completion descriptor. Since the\nfunction never skips the outer encapsulation, this mismatch triggers:\n\n- BUG_ON(hdr.ipv4-\u003eprotocol != IPPROTO_TCP), because the outer\n  protocol is UDP (Geneve), not TCP.\n- BUG_ON(hdr.eth-\u003eh_proto != ...), when the tunnel\u0027s outer and inner\n  IP versions differ (e.g. outer IPv6/inner IPv4 or vice versa).\n\nCheck VMXNET3_RCD_HDR_INNER_SHIFT up front and bail out, since the\nfunction cannot locate the inner header it would need to parse. Also\nconvert the remaining BUG_ON()s in this function to return 0\ndefensively.",
  "id": "GHSA-m243-8cm2-374c",
  "modified": "2026-08-19T18:32:13Z",
  "published": "2026-08-10T15:33:45Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-68299"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/28cb5d8d13b4c1faf3f688f62e5df82fe7b438d8"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/28e382646417c7e2be9c9a7079eddf627ff52b90"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/2ddf51fcb6dd7d55ceef38e2e1a5ab2ab7fd47b0"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/34a71f5361fc3adb5b7138da78750b0d535a8252"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/4fdb0f162ccdbe9626863b10003855703253fa29"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/667b6e52048eaf4dbcf1707ed87ffd44abb9cb38"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/b28596baf87e25a078789f1c05817c8a3bf71257"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/fbab6b73cc086e32698c86e43d1b16bf17d24c36"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ]
}

CVE-2026-68299 (GCVE-0-2026-68299)

Vulnerability from cvelistv5 – Published: 2026-08-10 12:02 – Updated: 2026-08-19 16:32

Title

vmxnet3: fix BUG_ON in vmxnet3_get_hdr_len() for Geneve packets

Summary

In the Linux kernel, the following vulnerability has been resolved: vmxnet3: fix BUG_ON in vmxnet3_get_hdr_len() for Geneve packets vmxnet3_get_hdr_len() assumes gdesc->rcd.v4/v6/tcp always describe the outer header, but for a Geneve-encapsulated packet the device can set them based on the inner header instead, signalled by the VMXNET3_RCD_HDR_INNER_SHIFT bit in the completion descriptor. Since the function never skips the outer encapsulation, this mismatch triggers: - BUG_ON(hdr.ipv4->protocol != IPPROTO_TCP), because the outer protocol is UDP (Geneve), not TCP. - BUG_ON(hdr.eth->h_proto != ...), when the tunnel's outer and inner IP versions differ (e.g. outer IPv6/inner IPv4 or vice versa). Check VMXNET3_RCD_HDR_INNER_SHIFT up front and bail out, since the function cannot locate the inner header it would need to parse. Also convert the remaining BUG_ON()s in this function to return 0 defensively.

Severity

7.5 (High)


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

Assigner

Linux mitre root Scorecard

References

8 references

URL	Tags
https://git.kernel.org/stable/c/2ddf51fcb6dd7d55c…
https://git.kernel.org/stable/c/fbab6b73cc086e326…
https://git.kernel.org/stable/c/28e382646417c7e2b…
https://git.kernel.org/stable/c/667b6e52048eaf4db…
https://git.kernel.org/stable/c/28cb5d8d13b4c1faf…
https://git.kernel.org/stable/c/4fdb0f162ccdbe962…
https://git.kernel.org/stable/c/b28596baf87e25a07…
https://git.kernel.org/stable/c/34a71f5361fc3adb5…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 45dac1d6ea045ae56e4df8d9c70c92c7412bd4fc , < 2ddf51fcb6dd7d55ceef38e2e1a5ab2ab7fd47b0 (git) Affected: 45dac1d6ea045ae56e4df8d9c70c92c7412bd4fc , < fbab6b73cc086e32698c86e43d1b16bf17d24c36 (git) Affected: 45dac1d6ea045ae56e4df8d9c70c92c7412bd4fc , < 28e382646417c7e2be9c9a7079eddf627ff52b90 (git) Affected: 45dac1d6ea045ae56e4df8d9c70c92c7412bd4fc , < 667b6e52048eaf4dbcf1707ed87ffd44abb9cb38 (git) Affected: 45dac1d6ea045ae56e4df8d9c70c92c7412bd4fc , < 28cb5d8d13b4c1faf3f688f62e5df82fe7b438d8 (git) Affected: 45dac1d6ea045ae56e4df8d9c70c92c7412bd4fc , < 4fdb0f162ccdbe9626863b10003855703253fa29 (git) Affected: 45dac1d6ea045ae56e4df8d9c70c92c7412bd4fc , < b28596baf87e25a078789f1c05817c8a3bf71257 (git) Affected: 45dac1d6ea045ae56e4df8d9c70c92c7412bd4fc , < 34a71f5361fc3adb5b7138da78750b0d535a8252 (git)
Linux	Linux	Affected: 4.2 Unaffected: 0 , < 4.2 (semver) Unaffected: 5.10.265 , ≤ 5.10.* (semver) Unaffected: 5.15.216 , ≤ 5.15.* (semver) Unaffected: 6.1.183 , ≤ 6.1.* (semver) Unaffected: 6.6.148 , ≤ 6.6.* (semver) Unaffected: 6.12.101 , ≤ 6.12.* (semver) Unaffected: 6.18.42 , ≤ 6.18.* (semver) Unaffected: 7.1.6 , ≤ 7.1.* (semver) Unaffected: 7.2 , ≤ * (original_commit_for_fix)

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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/net/vmxnet3/vmxnet3_drv.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "2ddf51fcb6dd7d55ceef38e2e1a5ab2ab7fd47b0",
              "status": "affected",
              "version": "45dac1d6ea045ae56e4df8d9c70c92c7412bd4fc",
              "versionType": "git"
            },
            {
              "lessThan": "fbab6b73cc086e32698c86e43d1b16bf17d24c36",
              "status": "affected",
              "version": "45dac1d6ea045ae56e4df8d9c70c92c7412bd4fc",
              "versionType": "git"
            },
            {
              "lessThan": "28e382646417c7e2be9c9a7079eddf627ff52b90",
              "status": "affected",
              "version": "45dac1d6ea045ae56e4df8d9c70c92c7412bd4fc",
              "versionType": "git"
            },
            {
              "lessThan": "667b6e52048eaf4dbcf1707ed87ffd44abb9cb38",
              "status": "affected",
              "version": "45dac1d6ea045ae56e4df8d9c70c92c7412bd4fc",
              "versionType": "git"
            },
            {
              "lessThan": "28cb5d8d13b4c1faf3f688f62e5df82fe7b438d8",
              "status": "affected",
              "version": "45dac1d6ea045ae56e4df8d9c70c92c7412bd4fc",
              "versionType": "git"
            },
            {
              "lessThan": "4fdb0f162ccdbe9626863b10003855703253fa29",
              "status": "affected",
              "version": "45dac1d6ea045ae56e4df8d9c70c92c7412bd4fc",
              "versionType": "git"
            },
            {
              "lessThan": "b28596baf87e25a078789f1c05817c8a3bf71257",
              "status": "affected",
              "version": "45dac1d6ea045ae56e4df8d9c70c92c7412bd4fc",
              "versionType": "git"
            },
            {
              "lessThan": "34a71f5361fc3adb5b7138da78750b0d535a8252",
              "status": "affected",
              "version": "45dac1d6ea045ae56e4df8d9c70c92c7412bd4fc",
              "versionType": "git"
            }
          ]
        },
        {
          "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": "4.2"
            },
            {
              "lessThan": "4.2",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.265",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.216",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.183",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.148",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.101",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.42",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.6",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.10.265",
                  "versionStartIncluding": "4.2",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.15.216",
                  "versionStartIncluding": "4.2",
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                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.1.183",
                  "versionStartIncluding": "4.2",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.148",
                  "versionStartIncluding": "4.2",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.101",
                  "versionStartIncluding": "4.2",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.42",
                  "versionStartIncluding": "4.2",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.1.6",
                  "versionStartIncluding": "4.2",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2",
                  "versionStartIncluding": "4.2",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nvmxnet3: fix BUG_ON in vmxnet3_get_hdr_len() for Geneve packets\n\nvmxnet3_get_hdr_len() assumes gdesc-\u003ercd.v4/v6/tcp always describe the\nouter header, but for a Geneve-encapsulated packet the device can set\nthem based on the inner header instead, signalled by the\nVMXNET3_RCD_HDR_INNER_SHIFT bit in the completion descriptor. Since the\nfunction never skips the outer encapsulation, this mismatch triggers:\n\n- BUG_ON(hdr.ipv4-\u003eprotocol != IPPROTO_TCP), because the outer\n  protocol is UDP (Geneve), not TCP.\n- BUG_ON(hdr.eth-\u003eh_proto != ...), when the tunnel\u0027s outer and inner\n  IP versions differ (e.g. outer IPv6/inner IPv4 or vice versa).\n\nCheck VMXNET3_RCD_HDR_INNER_SHIFT up front and bail out, since the\nfunction cannot locate the inner header it would need to parse. Also\nconvert the remaining BUG_ON()s in this function to return 0\ndefensively."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.5,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:N - The bug is triggered purely by a received Geneve-encapsulated packet processed in the vmxnet3 RX completion path (vmxnet3_rq_rx_complete -\u003e vmxnet3_get_hdr_len); any remote host that can deliver such a frame to a VMware guest\u0027s vmxnet3 interface reaches the code, with no local access required.\nAC:L - The attacker only needs to send Geneve-encapsulated TCP traffic larger than the MTU to the target; the device then sets rcd.v4/v6/tcp from the inner header and the outer UDP protocol (or an outer/inner IP version mismatch) deterministically hits the BUG_ON, with no race or memory-layout dependency.\nPR:N - Packet reception and header-length estimation occur in the driver\u0027s NAPI RX path before any socket, credential, or authentication check, so an entirely unauthenticated remote sender triggers it.\nUI:N - The panic happens during normal NAPI RX processing of an incoming packet; no action by any local user or administrator is needed.\nS:U - The BUG_ON crashes the kernel that owns the vmxnet3 interface, and impact stays entirely within that kernel\u0027s security authority with no crossing into the hypervisor or another domain.\nC:N - The header parsing is bounded by the explicit skb_headlen()/maplen checks, so no out-of-bounds read occurs and no kernel memory contents are disclosed to the attacker before the BUG_ON aborts.\nI:N - No out-of-bounds or attacker-controlled write occurs; the mismatch is caught by the BUG_ON assertion, which halts execution rather than corrupting kernel memory or control flow.\nA:H - Hitting BUG_ON() in softirq/NAPI context oopses and panics the kernel, taking down the entire guest; a remote attacker can repeat it with a single crafted Geneve packet stream for a persistent denial of service."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-19T16:32:48.545Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/2ddf51fcb6dd7d55ceef38e2e1a5ab2ab7fd47b0"
        },
        {
          "url": "https://git.kernel.org/stable/c/fbab6b73cc086e32698c86e43d1b16bf17d24c36"
        },
        {
          "url": "https://git.kernel.org/stable/c/28e382646417c7e2be9c9a7079eddf627ff52b90"
        },
        {
          "url": "https://git.kernel.org/stable/c/667b6e52048eaf4dbcf1707ed87ffd44abb9cb38"
        },
        {
          "url": "https://git.kernel.org/stable/c/28cb5d8d13b4c1faf3f688f62e5df82fe7b438d8"
        },
        {
          "url": "https://git.kernel.org/stable/c/4fdb0f162ccdbe9626863b10003855703253fa29"
        },
        {
          "url": "https://git.kernel.org/stable/c/b28596baf87e25a078789f1c05817c8a3bf71257"
        },
        {
          "url": "https://git.kernel.org/stable/c/34a71f5361fc3adb5b7138da78750b0d535a8252"
        }
      ],
      "title": "vmxnet3: fix BUG_ON in vmxnet3_get_hdr_len() for Geneve packets",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-68299",
    "datePublished": "2026-08-10T12:02:33.213Z",
    "dateReserved": "2026-07-30T09:28:09.380Z",
    "dateUpdated": "2026-08-19T16:32:48.545Z",
    "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.

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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Action not permitted

GHSA-M243-8CM2-374C

CVE-2026-68299 (GCVE-0-2026-68299)

Tags

Sightings

Nomenclature

Related by attack behaviour