netfilter: conntrack: fix wrong ct->timeout value

{
  "id": "5e5592c338c727d00d2ff0a18cbb9d34869b30d4430f20304c74b970db805956",
  "url": "https://osv.dev/vulnerability/CVE-2023-53635",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "netfilter: conntrack: fix wrong ct->timeout value",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: netfilter: conntrack: fix wrong ct->timeout value (struct nf_conn)->timeout is an interval before the conntrack confirmed. After confirmed, it becomes a timestamp. It is observed that timeout of an unconfirmed conntrack: - Set by calling ctnetlink_change_timeout(). As a result, `nfct_time_stamp` was wrongly added to `ct->timeout` twice. - Get by calling ctnetlink_dump_timeout(). As a result, `nfct_time_stamp` was wrongly subtracted. Call Trace: dump_stack_lvl ctnetlink_dump_timeout __ctnetlink_glue_build ctnetlink_glue_build __nfqnl_enqueue_packet nf_queue nf_hook_slow ip_mc_output ? __pfx_ip_finish_output ip_send_skb ? __pfx_dst_output udp_send_skb udp_sendmsg ? __pfx_ip_generic_getfrag sock_sendmsg Separate the 2 cases in: - Setting `ct->timeout` in __nf_ct_set_timeout(). - Getting `ct->timeout` in ctnetlink_dump_timeout(). Pablo appends: Update ctnetlink to set up the timeout _after_ the IPS_CONFIRMED flag is set on, otherwise conntrack creation via ctnetlink breaks. Note that the problem described in this patch occurs since the introduction of the nfnetlink_queue conntrack support, select a sufficiently old Fixes: tag for -stable kernel to pick up this fix.",
    "evidence": "osv:CVE-2023-53635",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "6.1.28",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.2.15",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.3.2",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "high",
    "structured": {
      "id": "CVE-2023-53635",
      "aliases": [
        "CVE-2023-53635"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
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                  "fixed": "80c5ba0078e20d926d11d0778f9a43902664ebf0"
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                  "fixed": "ff5e4ac8dd7be7f1faba955c5779a68571eeb0f8"
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                {
                  "fixed": "f612ae1ab4793701caf39386fb3b7f4b3ef44e48"
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                {
                  "fixed": "73db1b8f2bb6725b7391e85aab41fdf592b3c0c1"
                }
              ]
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2023-53635.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "4.4.0"
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                  "fixed": "6.1.28"
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            {
              "type": "ECOSYSTEM",
              "events": [
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                  "introduced": "6.2.0"
                },
                {
                  "fixed": "6.2.15"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.3.0"
                },
                {
                  "fixed": "6.3.2"
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          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2023-53635.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:48.004390403Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/73db1b8f2bb6725b7391e85aab41fdf592b3c0c1",
        "https://git.kernel.org/stable/c/80c5ba0078e20d926d11d0778f9a43902664ebf0",
        "https://git.kernel.org/stable/c/f612ae1ab4793701caf39386fb3b7f4b3ef44e48",
        "https://git.kernel.org/stable/c/ff5e4ac8dd7be7f1faba955c5779a68571eeb0f8",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2023/53xxx/CVE-2023-53635.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2023-53635",
        "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/2023/53xxx/CVE-2023-53635.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2023-53635",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 515868,
  "published_at": "2025-10-07T15:19:36.973+00:00"
}