GHSA-M243-8CM2-374C

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



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