net: gso: fix ownership in __udp_gso_segment

{
  "id": "2285215872950d395004132a2038c1892185d17d0e8740a7b6d5c68e201c1150",
  "url": "https://osv.dev/vulnerability/CVE-2025-21926",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "net: gso: fix ownership in __udp_gso_segment",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: net: gso: fix ownership in __udp_gso_segment In __udp_gso_segment the skb destructor is removed before segmenting the skb but the socket reference is kept as-is. This is an issue if the original skb is later orphaned as we can hit the following bug: kernel BUG at ./include/linux/skbuff.h:3312! (skb_orphan) RIP: 0010:ip_rcv_core+0x8b2/0xca0 Call Trace: ip_rcv+0xab/0x6e0 __netif_receive_skb_one_core+0x168/0x1b0 process_backlog+0x384/0x1100 __napi_poll.constprop.0+0xa1/0x370 net_rx_action+0x925/0xe50 The above can happen following a sequence of events when using OpenVSwitch, when an OVS_ACTION_ATTR_USERSPACE action precedes an OVS_ACTION_ATTR_OUTPUT action: 1. OVS_ACTION_ATTR_USERSPACE is handled (in do_execute_actions): the skb goes through queue_gso_packets and then __udp_gso_segment, where its destructor is removed. 2. The segments' data are copied and sent to userspace. 3. OVS_ACTION_ATTR_OUTPUT is handled (in do_execute_actions) and the same original skb is sent to its path. 4. If it later hits skb_orphan, we hit the bug. Fix this by also removing the reference to the socket in __udp_gso_segment.",
    "evidence": "osv:CVE-2025-21926",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
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            "evidence": "/affected/1/ranges"
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    "severity": "high",
    "structured": {
      "id": "CVE-2025-21926",
      "aliases": [
        "CVE-2025-21926"
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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": "2026-10-28T02:30:51.412825911Z",
      "provider": "osv",
      "references": [
        "https://cert-portal.siemens.com/productcert/html/ssa-019113.html",
        "https://cert-portal.siemens.com/productcert/html/ssa-457936.html",
        "https://git.kernel.org/stable/c/01a83237644d6822bc7df2c5564fc81b0df84358",
        "https://git.kernel.org/stable/c/084819b0d8b1bd433b90142371eb9450d657f8ca",
        "https://git.kernel.org/stable/c/455217ac9db0cf9349b3933664355e907bb1a569",
        "https://git.kernel.org/stable/c/9f28205ddb76e86cac418332e952241d85fed0dc",
        "https://git.kernel.org/stable/c/a2d1cca955ed34873e524cc2e6e885450d262f05",
        "https://git.kernel.org/stable/c/c32da44cc9298eaa6109e3fc2c2b4e07cc4bf11b",
        "https://git.kernel.org/stable/c/e8db70537878e1bb3fd83e5abcc6feefc0587828",
        "https://git.kernel.org/stable/c/ee01b2f2d7d0010787c2343463965bbc283a497f",
        "https://lists.debian.org/debian-lts-announce/2025/05/msg00030.html",
        "https://lists.debian.org/debian-lts-announce/2025/05/msg00045.html",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/21xxx/CVE-2025-21926.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2025-21926",
        "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
      ],
      "provider_metadata": {
        "cna_assigner": "Linux",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/21xxx/CVE-2025-21926.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2025-21926",
        "evidence": "/id"
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    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 519651,
  "published_at": "2025-04-01T15:40:57.882+00:00"
}