tcp: reject non zerocopy devmem tx

{
  "id": "16470261e0f9f4ec24bb4a5afb6e554d3294d3b62bf948c5f8929989b05b54d5",
  "url": "https://osv.dev/vulnerability/CVE-2026-90051",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "tcp: reject non zerocopy devmem tx",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: tcp: reject non zerocopy devmem tx Devmem tcp tx doesn't work without zero-copy, however it's not currently enforced if NETIF_F_SG isn't present. In this case, tcp_sendmsg_locked() will try the copy path and try to copy data from an iovec which consists of offsets into the dma-buf and would normally fail. Moreover, d9c56501c72fd (\"net: tcp: block mixing readable and unreadable frags\") relies on that and assumes that the devmem binding is present IFF we're using the zero-copy path, which can be used to mix net-iov and pages in a single skb, and break invariants. Let's reject devmem tx without zero-copy. Note, the parameter check the patch is modifying is too loose, we can create an io_uring request with dmabuf_id and all ZC flags, but which won't have the binding. We replace it with stricter validation.",
    "evidence": "osv:CVE-2026-90051",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "6.18.52",
            "evidence": "/affected/1/ranges"
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          {
            "value": "7.2.6",
            "evidence": "/affected/1/ranges"
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    "severity": "high",
    "structured": {
      "id": "CVE-2026-90051",
      "aliases": [
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      "metrics": [
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          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"
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        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.16.0"
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                {
                  "fixed": "6.18.52"
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              ]
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            {
              "type": "ECOSYSTEM",
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                  "introduced": "6.19.0"
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            "ecosystem": "Linux"
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      ],
      "modified": "2026-10-28T02:30:50.942034513Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/125755776bc6d4dd53eaf551c87e3d460625d638",
        "https://git.kernel.org/stable/c/2151b2bcf6fcec52665f606eed20da068447f0b7",
        "https://git.kernel.org/stable/c/b04326c7927af7048fd4e730f5770cca350d0a60",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/90xxx/CVE-2026-90051.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-90051",
        "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
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        "cna_assigner": "Linux",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/90xxx/CVE-2026-90051.json"
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        "value": "CVE-2026-90051",
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    "severity_evidence": "/severity/0/score"
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  "source_id": "core-osv",
  "document_id": 519558,
  "published_at": "2026-09-17T16:05:37.62+00:00"
}