net/mlx5e: macsec: fix use-after-free of metadata_dst on RX SC delete

{
  "id": "263184149d8ad60ec6dced76d38d1b25501c6fd20f9a029ce252a165179aa526",
  "url": "https://osv.dev/vulnerability/CVE-2026-72072",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "net/mlx5e: macsec: fix use-after-free of metadata_dst on RX SC delete",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: net/mlx5e: macsec: fix use-after-free of metadata_dst on RX SC delete When an offloaded MACsec RX SC is deleted, macsec_del_rxsc_ctx() freed the per-SC metadata_dst with metadata_dst_free(), which kfree()s the object unconditionally and ignores the dst reference count. The RX datapath in mlx5e_macsec_offload_handle_rx_skb() looks up the SC under rcu_read_lock() via xa_load(), takes a reference with dst_hold() and attaches the dst to the skb with skb_dst_set(). A reader that already obtained the rx_sc pointer can race with the delete path and operate on freed memory. Fix the owner side by dropping the reference with dst_release() instead of freeing unconditionally, and convert the RX datapath to dst_hold_safe() so a reader racing the SC delete cannot attach a dst whose last reference was just dropped; only attach it when a reference was actually taken. mlx5e_macsec_add_rxsc() also published sc_xarray_element via xa_alloc() before rx_sc->md_dst was allocated and initialised, so a datapath reader that looked the SC up by fs_id could observe rx_sc with md_dst still NULL or, on weakly-ordered architectures, a non-NULL md_dst pointer whose contents were not yet visible. NULL-check the xa_load() result and md_dst on the datapath, and reorder add_rxsc() so the xa_alloc() publish happens only after md_dst is fully initialised; the xarray RCU publish then pairs with the rcu_read_lock()/xa_load() in the datapath. Note: ",
    "evidence": "osv:CVE-2026-72072",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
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            "value": "6.1.178",
            "evidence": "/affected/1/ranges"
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            "value": "6.12.97",
            "evidence": "/affected/1/ranges"
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          {
            "value": "6.18.40",
            "evidence": "/affected/1/ranges"
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          {
            "value": "7.1.5",
            "evidence": "/affected/1/ranges"
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        "affected_versions": []
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    "severity": "high",
    "structured": {
      "id": "CVE-2026-72072",
      "aliases": [
        "CVE-2026-72072"
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      "metrics": [
        {
          "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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      ],
      "modified": "2026-10-28T02:30:40.459516870Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/088873af13590ebde10de2ade847f57a05ec61c6",
        "https://git.kernel.org/stable/c/218cc15a4c907659ad4b0e68c535c61594311205",
        "https://git.kernel.org/stable/c/4a5073b7b30243658f58b2d2d35a823da7fd34d9",
        "https://git.kernel.org/stable/c/b1a4d0c568bbb52c7c04f4fce3c097dae89ed6cb",
        "https://git.kernel.org/stable/c/de74d8fd10291763d97b218f09adcc7513c975e4",
        "https://git.kernel.org/stable/c/ed3cc4218070d6b98bf5fb456dccae424fd38c4f",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/72xxx/CVE-2026-72072.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-72072",
        "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
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      "provider_metadata": {
        "cna_assigner": "Linux",
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    "related_cves": [
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        "value": "CVE-2026-72072",
        "evidence": "/id"
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    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
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  "source_id": "core-osv",
  "document_id": 508204,
  "published_at": "2026-08-15T05:52:23.946+00:00"
}