CVE-2026-31678 (GCVE-0-2026-31678)
Vulnerability from cvelistv5
Published
2026-04-25 08:46
Modified
2026-08-05 12:24
Severity ?
7.8 (High) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: openvswitch: defer tunnel netdev_put to RCU release ovs_netdev_tunnel_destroy() may run after NETDEV_UNREGISTER already detached the device. Dropping the netdev reference in destroy can race with concurrent readers that still observe vport->dev. Do not release vport->dev in ovs_netdev_tunnel_destroy(). Instead, let vport_netdev_free() drop the reference from the RCU callback, matching the non-tunnel destroy path and avoiding additional synchronization under RTNL.
References
Impacted products
Vendor Product Version
Linux Linux Version: a9020fde67a6eb77f8130feff633189f99264db1
Version: a9020fde67a6eb77f8130feff633189f99264db1
Version: a9020fde67a6eb77f8130feff633189f99264db1
Version: a9020fde67a6eb77f8130feff633189f99264db1
Version: a9020fde67a6eb77f8130feff633189f99264db1
Version: a9020fde67a6eb77f8130feff633189f99264db1
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{
  "containers": {
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      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/openvswitch/vport-netdev.c"
          ],
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          "product": "Linux",
          "programFiles": [
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          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
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              "version": "4.3"
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              "version": "0",
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              "status": "unaffected",
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              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.21",
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              "lessThanOrEqual": "6.19.*",
              "status": "unaffected",
              "version": "6.19.11",
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            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.0",
              "versionType": "original_commit_for_fix"
            }
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      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.1.168",
                  "versionStartIncluding": "4.3",
                  "vulnerable": true
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                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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              "negate": false,
              "operator": "OR"
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      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nopenvswitch: defer tunnel netdev_put to RCU release\n\novs_netdev_tunnel_destroy() may run after NETDEV_UNREGISTER already\ndetached the device. Dropping the netdev reference in destroy can race\nwith concurrent readers that still observe vport-\u003edev.\n\nDo not release vport-\u003edev in ovs_netdev_tunnel_destroy(). Instead, let\nvport_netdev_free() drop the reference from the RCU callback, matching\nthe non-tunnel destroy path and avoiding additional synchronization\nunder RTNL."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.8,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - The vulnerable destroy path is reached through local Generic Netlink/rtnetlink control operations that create or delete Open vSwitch tunnel vports. Remote tunnel packets alone do not invoke `ovs_netdev_tunnel_destroy()`.\nAC:L - This is a race/lifetime bug, but the attacker can control both sides by repeatedly deleting tunnel vports while concurrently driving RCU readers such as vport get/dump, packet execute, or datapath traffic. No rare external condition is required.\nPR:L - Creating and deleting OVS datapaths/vports requires `CAP_NET_ADMIN`, but the OVS Generic Netlink families are netns-aware and use `GENL_UNS_ADMIN_PERM`, making this reachable with CAP_NET_ADMIN in an unprivileged user namespace. This is Low privileges rather than High.\nUI:N - No victim user action is needed once the local attacker can issue the relevant netlink operations. The attacker can trigger creation, deletion, and racing reader activity directly.\nS:U - The vulnerability is a kernel memory lifetime error within the same host kernel security authority. It is a standard local kernel privilege-escalation/DoS class issue, not a VM or hardware boundary escape.\nC:H - The early `netdev_put()` can free the `net_device` while RCU readers still dereference `vport-\u003edev`, creating a use-after-free. Per kernel CVSS guidance, UAFs are scored as High confidentiality impact because they can be developed into kernel memory disclosure primitives.\nI:H - The stale `net_device` pointer can be reused after free by kernel readers/writers and may reach function-pointer-bearing netdev paths. Per guidance, a use-after-free is scored as High integrity impact because heap reuse can enable arbitrary write or code execution.\nA:H - The bug can at minimum crash or oops the kernel through NULL/stale `vport-\u003edev` dereferences and has related observed OVS netdev lifetime splats. A kernel UAF also warrants High availability impact."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T12:24:24.631Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/9d56aced21fb9c104e8a3f3be9b21fbafe448ffc"
        },
        {
          "url": "https://git.kernel.org/stable/c/42f0d3d81209654c08ffdde5a34b9b92d2645896"
        },
        {
          "url": "https://git.kernel.org/stable/c/bbe7bd722bfaea36aab3da6cc60fb4a05c644643"
        },
        {
          "url": "https://git.kernel.org/stable/c/98b726ab5e2a4811e27c28e4d041f75bba147eab"
        },
        {
          "url": "https://git.kernel.org/stable/c/b8c56a3fc5d879c0928f207a756b0f067f06c6a8"
        },
        {
          "url": "https://git.kernel.org/stable/c/6931d21f87bc6d657f145798fad0bf077b82486c"
        }
      ],
      "title": "openvswitch: defer tunnel netdev_put to RCU release",
      "x_generator": {
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      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-31678",
    "datePublished": "2026-04-25T08:46:54.476Z",
    "dateReserved": "2026-03-09T15:48:24.130Z",
    "dateUpdated": "2026-08-05T12:24:24.631Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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