net: fix a memleak when uncloning an skb dst and its metadata

{
  "id": "ee51610f3e03817c12c8d97dad7107c4b46fa5b6816147e1eaf58c9ce887ca6a",
  "url": "https://osv.dev/vulnerability/CVE-2022-48809",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "net: fix a memleak when uncloning an skb dst and its metadata",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: net: fix a memleak when uncloning an skb dst and its metadata When uncloning an skb dst and its associated metadata, a new dst+metadata is allocated and later replaces the old one in the skb. This is helpful to have a non-shared dst+metadata attached to a specific skb. The issue is the uncloned dst+metadata is initialized with a refcount of 1, which is increased to 2 before attaching it to the skb. When tun_dst_unclone returns, the dst+metadata is only referenced from a single place (the skb) while its refcount is 2. Its refcount will never drop to 0 (when the skb is consumed), leading to a memory leak. Fix this by removing the call to dst_hold in tun_dst_unclone, as the dst+metadata refcount is already 1.",
    "evidence": "osv:CVE-2022-48809",
    "products": [
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          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
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    "severity": "unknown",
    "structured": {
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      "aliases": [
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      "modified": "2026-10-28T02:30:51.566680627Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/00e6d6c3bc14dfe32824e2c515f0e0f2d6ecf2f1",
        "https://git.kernel.org/stable/c/0be943916d781df2b652793bb2d3ae4f9624c10a",
        "https://git.kernel.org/stable/c/4ac84498fbe84a00e7aef185e2bb3e40ce71eca4",
        "https://git.kernel.org/stable/c/8b1087b998e273f07be13dcb5f3ca4c309c7f108",
        "https://git.kernel.org/stable/c/9eeabdf17fa0ab75381045c867c370f4cc75a613",
        "https://git.kernel.org/stable/c/a80817adc2a4c1ba26a7aa5f3ed886e4a18dff88",
        "https://git.kernel.org/stable/c/c1ff27d100e2670b03cbfddb9117e5f9fc672540",
        "https://git.kernel.org/stable/c/fdcb263fa5cda15b8cb24a641fa2718c47605314",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2022/48xxx/CVE-2022-48809.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2022-48809",
        "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
      ],
      "provider_metadata": {
        "cna_assigner": "Linux",
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        "evidence": "/id"
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    "security_relevant": true,
    "severity_evidence": null
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  "source_id": "core-osv",
  "document_id": 520081,
  "published_at": "2024-07-16T11:43:59.757+00:00"
}