CVE-2026-97608 (GCVE-0-2026-97608)

Vulnerability from cvelistv5 – Published: 2026-09-25 10:22 – Updated: 2026-09-25 14:41
VLAI
Title
netfilter: nf_log: unregister loggers before per-net teardown
Summary
In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_log: unregister loggers before per-net teardown nf_log_syslog and nfnetlink_log unregister their per-network namespace operations before unregistering their global logger backends. This leaves a window where a sysctl or netlink writer can rebind the still- registered logger after the per-net pre-exit callback cleared the old selection. The race looks like this: CPU 0 CPU 1 ---- ---- unregister_pernet_subsys() nf_log_unset(net, logger) net->nf.nf_loggers[pf] = NULL lock nf_log_mutex find logger in loggers[][] net->nf.nf_loggers[pf] = logger unlock nf_log_mutex nf_log_unregister(logger) lock nf_log_mutex loggers[pf][type] = NULL unlock nf_log_mutex synchronize_rcu() module exit returns module core frees backend memory Later, a sysctl read or packet logging operation can dereference the stale per-net logger pointer. Fix this by unregistering the global logger backends before tearing down per-net state. Once the global registrations are gone, later writers can no longer rebind the logger. unregister_pernet_subsys() already waits for an RCU grace period after the pre-exit callback clears the per-net selection, while nf_log_unregister() continues to cover readers of the global logger table. Apply this ordering fix to both nf_log backends that combine per-net teardown with global logger registration.
Severity
7 (High)
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 5b023fc8d8e0997e0b7ea6506d243afd5478c96e , < eaec35fae8f2052c1878a5c7cc7699d8357d79f2 (git)
Affected: 5b023fc8d8e0997e0b7ea6506d243afd5478c96e , < 64803ba0a05791cf9ca874466480e4c4cadaf7ab (git)
Affected: 5b023fc8d8e0997e0b7ea6506d243afd5478c96e , < dce24f3a146948595bb1b86347f31e20b4975daa (git)
Affected: 5b023fc8d8e0997e0b7ea6506d243afd5478c96e , < 2c018cc4842c33f0c732962e2ab58635e8ae5823 (git)
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Linux Linux Affected: 3.10
Unaffected: 0 , < 3.10 (semver)
Unaffected: 6.12.111 , ≤ 6.12.* (semver)
Unaffected: 6.18.53 , ≤ 6.18.* (semver)
Unaffected: 7.2.7 , ≤ 7.2.* (semver)
Unaffected: 7.3-rc3 , ≤ * (original_commit_for_fix)
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{
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      "affected": [
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          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/netfilter/nf_log_syslog.c",
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          "vendor": "Linux",
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              "versionType": "semver"
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              "version": "6.18.53",
              "versionType": "semver"
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              "status": "unaffected",
              "version": "7.2.7",
              "versionType": "semver"
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              "status": "unaffected",
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              "versionType": "original_commit_for_fix"
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                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.111",
                  "versionStartIncluding": "3.10",
                  "vulnerable": true
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                  "versionEndExcluding": "6.18.53",
                  "versionStartIncluding": "3.10",
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                  "versionEndExcluding": "7.3-rc3",
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      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: nf_log: unregister loggers before per-net teardown\n\nnf_log_syslog and nfnetlink_log unregister their per-network namespace\noperations before unregistering their global logger backends. This\nleaves a window where a sysctl or netlink writer can rebind the still-\nregistered logger after the per-net pre-exit callback cleared the old\nselection.\n\nThe race looks like this:\n\n  CPU 0                                 CPU 1\n  ----                                  ----\n  unregister_pernet_subsys()\n    nf_log_unset(net, logger)\n      net-\u003enf.nf_loggers[pf] = NULL\n\n                                        lock nf_log_mutex\n                                        find logger in loggers[][]\n                                        net-\u003enf.nf_loggers[pf] = logger\n                                        unlock nf_log_mutex\n\n  nf_log_unregister(logger)\n    lock nf_log_mutex\n    loggers[pf][type] = NULL\n    unlock nf_log_mutex\n    synchronize_rcu()\n  module exit returns\n  module core frees backend memory\n\nLater, a sysctl read or packet logging operation can dereference the\nstale per-net logger pointer.\n\nFix this by unregistering the global logger backends before tearing down\nper-net state. Once the global registrations are gone, later writers can\nno longer rebind the logger. unregister_pernet_subsys() already waits\nfor an RCU grace period after the pre-exit callback clears the per-net\nselection, while nf_log_unregister() continues to cover readers of the\nglobal logger table.\n\nApply this ordering fix to both nf_log backends that combine per-net\nteardown with global logger registration."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
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              "lang": "en",
              "value": "AV:L - Both sides of the race are local. One is module exit (nf_log_syslog_exit or nfnetlink_log_fini through delete_module). The other is a write to the net.netfilter.nf_log.\u003cpf\u003e sysctl, handled by nf_log_proc_dostring(), or an NFULNL_CFG_CMD_PF_BIND message over nfnetlink. No remote peer supplies anything that causes the stale nf_loggers[] pointer.\nAC:H - The attacker controls the rebind side, but the other side is a module unload that needs init-namespace CAP_SYS_MODULE. The attacker cannot make it happen. They must win the short window between nf_log_unset() in the per-net pre-exit and nf_log_unregister() while an admin unloads the module.\nPR:L - nf_log_proc_dostring() rebinds net-\u003enf.nf_loggers[pf] from the per-netns sysctl, which is writable in a non-init netns. The nfnetlink PF_BIND path only checks netlink_net_capable(CAP_NET_ADMIN). So user namespaces (unshare -Urn) are enough for the attacker\u0027s side.\nUI:N - No victim action on attacker-supplied content is needed. The module unload is an admin action outside the attacker\u0027s control and is already counted under AC:H.\nS:U - The stale logger pointer is used inside the same kernel. Nothing crosses a VM, IOMMU or other security boundary.\nC:H - After the module is freed, a sysctl read dereferences logger-\u003ename, and nf_log_packet() calls logger-\u003elogfn through the dangling nf_loggers[pf] pointer. This is a use-after-free of freed module memory that can be leveraged to disclose kernel memory.\nI:H - nf_log_packet() makes an indirect call through logger-\u003elogfn in the freed module\u0027s memory. If that memory is reused, this gives control-flow hijacking and memory corruption.\nA:H - Logging a packet, or reading the sysctl, after the logger module is gone faults on the unmapped or reused module memory and oopses the kernel."
            }
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        }
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      "providerMetadata": {
        "dateUpdated": "2026-09-25T14:41:31.026Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
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          "url": "https://git.kernel.org/stable/c/eaec35fae8f2052c1878a5c7cc7699d8357d79f2"
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          "url": "https://git.kernel.org/stable/c/64803ba0a05791cf9ca874466480e4c4cadaf7ab"
        },
        {
          "url": "https://git.kernel.org/stable/c/dce24f3a146948595bb1b86347f31e20b4975daa"
        },
        {
          "url": "https://git.kernel.org/stable/c/2c018cc4842c33f0c732962e2ab58635e8ae5823"
        }
      ],
      "title": "netfilter: nf_log: unregister loggers before per-net teardown",
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  "cveMetadata": {
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    "assignerShortName": "Linux",
    "cveId": "CVE-2026-97608",
    "datePublished": "2026-09-25T10:22:19.030Z",
    "dateReserved": "2026-09-24T16:01:01.158Z",
    "dateUpdated": "2026-09-25T14:41:31.026Z",
    "state": "PUBLISHED"
  },
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  "dataVersion": "5.2",
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      "cve": "CVE-2026-97608",
      "date": "2026-09-28",
      "epss": "0.00144",
      "percentile": "0.03084"
    },
    "microsoft_vex": {
      "current_release_date": "2026-09-27T23:53:11.000Z",
      "cve": "CVE-2026-97608",
      "id": "msrc_CVE-2026-97608",
      "initial_release_date": "2026-09-27T23:53:11.000Z",
      "product_status:known_affected": "1",
      "source": "Microsoft CSAF VEX",
      "status": "final",
      "title": "netfilter: nf_log: unregister loggers before per-net teardown",
      "url": "https://msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-97608.json",
      "version": "1"
    },
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                "product": "Linux",
                "programFiles": [
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                    "versionType": "git"
                  }
                ]
              },
              {
                "defaultStatus": "affected",
                "product": "Linux",
                "programFiles": [
                  "net/netfilter/nf_log_syslog.c",
                  "net/netfilter/nfnetlink_log.c"
                ],
                "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                "vendor": "Linux",
                "versions": [
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                    "versionType": "semver"
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        ],
        "cveTags": [],
        "descriptions": [
          {
            "lang": "en",
            "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: nf_log: unregister loggers before per-net teardown\n\nnf_log_syslog and nfnetlink_log unregister their per-network namespace\noperations before unregistering their global logger backends. This\nleaves a window where a sysctl or netlink writer can rebind the still-\nregistered logger after the per-net pre-exit callback cleared the old\nselection.\n\nThe race looks like this:\n\n  CPU 0                                 CPU 1\n  ----                                  ----\n  unregister_pernet_subsys()\n    nf_log_unset(net, logger)\n      net-\u003enf.nf_loggers[pf] = NULL\n\n                                        lock nf_log_mutex\n                                        find logger in loggers[][]\n                                        net-\u003enf.nf_loggers[pf] = logger\n                                        unlock nf_log_mutex\n\n  nf_log_unregister(logger)\n    lock nf_log_mutex\n    loggers[pf][type] = NULL\n    unlock nf_log_mutex\n    synchronize_rcu()\n  module exit returns\n  module core frees backend memory\n\nLater, a sysctl read or packet logging operation can dereference the\nstale per-net logger pointer.\n\nFix this by unregistering the global logger backends before tearing down\nper-net state. Once the global registrations are gone, later writers can\nno longer rebind the logger. unregister_pernet_subsys() already waits\nfor an RCU grace period after the pre-exit callback clears the per-net\nselection, while nf_log_unregister() continues to cover readers of the\nglobal logger table.\n\nApply this ordering fix to both nf_log backends that combine per-net\nteardown with global logger registration."
          }
        ],
        "id": "CVE-2026-97608",
        "lastModified": "2026-09-25T15:18:01.110",
        "metrics": {
          "cvssMetricV31": [
            {
              "cvssData": {
                "attackComplexity": "HIGH",
                "attackVector": "LOCAL",
                "availabilityImpact": "HIGH",
                "baseScore": 7.0,
                "baseSeverity": "HIGH",
                "confidentialityImpact": "HIGH",
                "integrityImpact": "HIGH",
                "privilegesRequired": "LOW",
                "scope": "UNCHANGED",
                "userInteraction": "NONE",
                "vectorString": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H",
                "version": "3.1"
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              "impactScore": 5.9,
              "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
              "type": "Secondary"
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        "published": "2026-09-25T11:17:14.870",
        "references": [
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/2c018cc4842c33f0c732962e2ab58635e8ae5823"
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            "url": "https://git.kernel.org/stable/c/64803ba0a05791cf9ca874466480e4c4cadaf7ab"
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            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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          }
        ],
        "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "vulnStatus": "Received"
      }
    }
  }
}



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