net: ip_gre: require CAP_NET_ADMIN in the device netns for changelink

{
  "id": "1b981da34ba3bd20eba27a4caac006040f22cd074272b0fa880f71221acec46f",
  "url": "https://osv.dev/vulnerability/CVE-2026-63829",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "net: ip_gre: require CAP_NET_ADMIN in the device netns for changelink",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: net: ip_gre: require CAP_NET_ADMIN in the device netns for changelink A tunnel changelink() operates on at most two netns, dev_net(dev) and the tunnel link netns t->net. They differ once the device is created in or moved to a netns other than the one the request runs in. The rtnl changelink path checks CAP_NET_ADMIN only against dev_net(dev), so a caller privileged there but not in t->net can rewrite a tunnel that lives in t->net. Add rtnl_dev_link_net_capable() next to rtnl_get_net_ns_capable() in net/core/rtnetlink.c. It requires CAP_NET_ADMIN in the link netns and is skipped when the link netns is dev_net(dev), where the rtnl path already checked it. The other patches in this series use the same helper. Gate ipgre_changelink() and erspan_changelink() with it, at the top of the op before any attribute is parsed, because the parsers update live tunnel fields first. ipgre_netlink_parms() sets t->collect_md before ip_tunnel_changelink() runs. Commit 8b484efd5cb4 (\"ip6: vti: Use ip6_tnl.net in vti6_siocdevprivate().\") added the same check on the ioctl path. This adds it on RTM_NEWLINK.",
    "evidence": "osv:CVE-2026-63829",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "5.10.261",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "5.15.212",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.1.178",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.6.145",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.12.95",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.18.38",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "7.1.3",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "high",
    "structured": {
      "id": "CVE-2026-63829",
      "aliases": [
        "CVE-2026-63829"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
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                  "introduced": "b57708add31494175be741ed3fd24023b50c3423"
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                {
                  "fixed": "19275943d8fe903eb7b9aa53e380e41efd042ada"
                },
                {
                  "fixed": "866b0f5ae599490bd496fd84581c68ac8b94e6af"
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                {
                  "fixed": "92b766fc55156e0da2ecd0c2302c971118f8a229"
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                {
                  "fixed": "e54c05ed3d9c28733fb9e5837219aca3691defa3"
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                {
                  "fixed": "9831bc9ecb402957810c2045c663fbfe9b09e296"
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                {
                  "fixed": "1697957eb0971d420dde42862b88eb43506a1105"
                },
                {
                  "fixed": "47b5d3d506609b08b2e1f7c14f0b681a1953d572"
                },
                {
                  "fixed": "8165f7ff57d9667d2bb477ef6af83ede7fed4ad7"
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              ]
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-63829.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "3.16.0"
                },
                {
                  "fixed": "5.10.261"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
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                  "introduced": "5.11.0"
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                  "introduced": "6.2.0"
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                  "introduced": "6.7.0"
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              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.13.0"
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                {
                  "fixed": "6.18.38"
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              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.19.0"
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                  "fixed": "7.1.3"
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              ]
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          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-63829.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:52.324822101Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/1697957eb0971d420dde42862b88eb43506a1105",
        "https://git.kernel.org/stable/c/19275943d8fe903eb7b9aa53e380e41efd042ada",
        "https://git.kernel.org/stable/c/47b5d3d506609b08b2e1f7c14f0b681a1953d572",
        "https://git.kernel.org/stable/c/8165f7ff57d9667d2bb477ef6af83ede7fed4ad7",
        "https://git.kernel.org/stable/c/866b0f5ae599490bd496fd84581c68ac8b94e6af",
        "https://git.kernel.org/stable/c/92b766fc55156e0da2ecd0c2302c971118f8a229",
        "https://git.kernel.org/stable/c/9831bc9ecb402957810c2045c663fbfe9b09e296",
        "https://git.kernel.org/stable/c/e54c05ed3d9c28733fb9e5837219aca3691defa3",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/63xxx/CVE-2026-63829.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-63829",
        "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/2026/63xxx/CVE-2026-63829.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-63829",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 521319,
  "published_at": "2026-07-19T12:02:23.191+00:00"
}