GHSA-H9RH-WF2H-CR4C

Vulnerability from github – Published: 2026-08-15 15:30 – Updated: 2026-08-17 06:33
VLAI
Details

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

vxlan: use pskb_network_may_pull() in route_shortcircuit()

route_shortcircuit() currently calls pskb_may_pull(skb, sizeof(struct iphdr)) (or ipv6hdr), which checks if bytes are available starting from skb->data.

However, in vxlan_xmit(), skb->data points to the MAC header, so skb_network_offset(skb) is ETH_HLEN (14 bytes). Using pskb_may_pull(skb, 20) only checks 20 bytes from skb->data (which is 14 bytes MAC header + 6 bytes of IP header), leaving the rest of the IP header potentially un-pulled in non-linear frags. Subsequent dereferences of ip_hdr(skb)->daddr can read beyond the pulled linear buffer length.

Fix this by using pskb_network_may_pull(), which adds skb_network_offset(skb) to the length check to ensure the full network header is present in the linear buffer.

Severity
9.8 (Critical)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Show details on source website
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{
  "affected": [],
  "aliases": [
    "CVE-2026-74473"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-08-15T13:17:52Z",
    "severity": "CRITICAL"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nvxlan: use pskb_network_may_pull() in route_shortcircuit()\n\nroute_shortcircuit() currently calls pskb_may_pull(skb, sizeof(struct iphdr))\n(or ipv6hdr), which checks if bytes are available starting from skb-\u003edata.\n\nHowever, in vxlan_xmit(), skb-\u003edata points to the MAC header, so\nskb_network_offset(skb) is ETH_HLEN (14 bytes). Using pskb_may_pull(skb, 20)\nonly checks 20 bytes from skb-\u003edata (which is 14 bytes MAC header + 6 bytes of\nIP header), leaving the rest of the IP header potentially un-pulled in non-linear\nfrags. Subsequent dereferences of ip_hdr(skb)-\u003edaddr can read beyond the pulled\nlinear buffer length.\n\nFix this by using pskb_network_may_pull(), which adds skb_network_offset(skb) to\nthe length check to ensure the full network header is present in the linear buffer.",
  "id": "GHSA-h9rh-wf2h-cr4c",
  "modified": "2026-08-17T06:33:48Z",
  "published": "2026-08-15T15:30:33Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-74473"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/26bb2dd0a8839617e2c79ffbbe1923f8e4bab9fb"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/42887be7c4cf283cce02cd0fb6411221167c8b6c"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/4f3f96e771a20263635bb5e1307c112d613b4bbd"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/aa0d31376d574ac858a40078431a77127bf04ee4"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/ee799977d7941dbfb11049e17edd9eaf4f8820f7"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}



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