FKIE_CVE-2026-74660

Vulnerability from fkie_nvd - Published: 2026-08-22 16:16 - Updated: 2026-10-14 13:10
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: netfilter: ebt_nflog: pin the NFLOG backend nf_log_unregister() runs after the per-net teardown so its final RCU grace period also drains readers that obtained the logger from a per-net binding. However, ebt_nflog passes an explicit ULOG log type to nf_log_packet() without holding a reference on the selected logger module, unlike the xt_NFLOG and nft_log frontends. An ebtables nflog rule can therefore remain callable while nfnetlink_log is unloaded. The resulting interleaving is: CPU 0 CPU 1 nfnetlink_log_fini() unregister_pernet_subsys() kfree(nfnl_log_pernet(net)) ebt_nflog_tg() nf_log_packet() nfulnl_log_packet() instance_lookup_get_rcu() The global ULOG logger is still registered at this point, so CPU 1 dereferences the per-net state after CPU 0 has freed it. KASAN reported: BUG: KASAN: slab-use-after-free in instance_lookup_get_rcu Read of size 8 at addr ff110001052e6210 by task poc/92 Call Trace: instance_lookup_get_rcu+0x1ce/0x1f0 [nfnetlink_log] nfulnl_log_packet+0x248/0x2fb0 [nfnetlink_log] nf_log_packet+0x204/0x300 ebt_nflog_tg+0x351/0x550 ebt_do_table+0xedf/0x22b0 Allocated by task 90: __kmalloc_noprof+0x186/0x470 ops_init+0x6d/0x420 register_pernet_operations+0x2f6/0x670 register_pernet_subsys+0x23/0x40 Freed by task 93: kfree+0x131/0x3c0 ops_undo_list+0x3e3/0x700 unregister_pernet_operations+0x232/0x490 unregister_pernet_subsys+0x1c/0x30 nfnetlink_log_fini+0x34/0x450 [nfnetlink_log] Acquire the ULOG logger module reference when an ebt_nflog rule is validated and release it when the rule is destroyed. Request the NFLOG backend for legacy callers when needed, matching xt_NFLOG. This prevents module teardown until all ebt_nflog rules have stopped using the logger.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/2cac4294f184c9bc19ff82552c62b80498694c39
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/30825970339c107bacaf7f61af90fcdb1f597ca1
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/394d7939c6b2b9e6bea0844c89efb5913168d898
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/3bcce49d617c593c7606083bfdb464a1761fa68d
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/47a119ec8a7e2d5c8c4e86fb1a56c4e696e500fb
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/6809379a860b9fccbb5435bf08343f6d081ac68d
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/9d8a94b48b393885e7f876c8ef68ed4da5012078
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/e2ab7e878bdbe80104c879c31fd2d82a476703b8
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/bridge/netfilter/ebt_nflog.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "3bcce49d617c593c7606083bfdb464a1761fa68d",
              "status": "affected",
              "version": "c83fa19603bdaeef17b815713dbbe3230c8a34ee",
              "versionType": "git"
            },
            {
              "lessThan": "394d7939c6b2b9e6bea0844c89efb5913168d898",
              "status": "affected",
              "version": "c83fa19603bdaeef17b815713dbbe3230c8a34ee",
              "versionType": "git"
            },
            {
              "lessThan": "2cac4294f184c9bc19ff82552c62b80498694c39",
              "status": "affected",
              "version": "c83fa19603bdaeef17b815713dbbe3230c8a34ee",
              "versionType": "git"
            },
            {
              "lessThan": "9d8a94b48b393885e7f876c8ef68ed4da5012078",
              "status": "affected",
              "version": "c83fa19603bdaeef17b815713dbbe3230c8a34ee",
              "versionType": "git"
            },
            {
              "lessThan": "6809379a860b9fccbb5435bf08343f6d081ac68d",
              "status": "affected",
              "version": "c83fa19603bdaeef17b815713dbbe3230c8a34ee",
              "versionType": "git"
            },
            {
              "lessThan": "47a119ec8a7e2d5c8c4e86fb1a56c4e696e500fb",
              "status": "affected",
              "version": "c83fa19603bdaeef17b815713dbbe3230c8a34ee",
              "versionType": "git"
            },
            {
              "lessThan": "e2ab7e878bdbe80104c879c31fd2d82a476703b8",
              "status": "affected",
              "version": "c83fa19603bdaeef17b815713dbbe3230c8a34ee",
              "versionType": "git"
            },
            {
              "lessThan": "30825970339c107bacaf7f61af90fcdb1f597ca1",
              "status": "affected",
              "version": "c83fa19603bdaeef17b815713dbbe3230c8a34ee",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "net/bridge/netfilter/ebt_nflog.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "4.12"
            },
            {
              "lessThan": "4.12",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.265",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.216",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.183",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.152",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.104",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.45",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.9",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: ebt_nflog: pin the NFLOG backend\n\nnf_log_unregister() runs after the per-net teardown so its final RCU\ngrace period also drains readers that obtained the logger from a per-net\nbinding.  However, ebt_nflog passes an explicit ULOG log type to\nnf_log_packet() without holding a reference on the selected logger module,\nunlike the xt_NFLOG and nft_log frontends.\n\nAn ebtables nflog rule can therefore remain callable while nfnetlink_log\nis unloaded.  The resulting interleaving is:\n\n  CPU 0                               CPU 1\n  nfnetlink_log_fini()\n    unregister_pernet_subsys()\n      kfree(nfnl_log_pernet(net))\n                                      ebt_nflog_tg()\n                                        nf_log_packet()\n                                          nfulnl_log_packet()\n                                            instance_lookup_get_rcu()\n\nThe global ULOG logger is still registered at this point, so CPU 1\ndereferences the per-net state after CPU 0 has freed it.  KASAN reported:\n\n  BUG: KASAN: slab-use-after-free in instance_lookup_get_rcu\n  Read of size 8 at addr ff110001052e6210 by task poc/92\n  Call Trace:\n   instance_lookup_get_rcu+0x1ce/0x1f0 [nfnetlink_log]\n   nfulnl_log_packet+0x248/0x2fb0 [nfnetlink_log]\n   nf_log_packet+0x204/0x300\n   ebt_nflog_tg+0x351/0x550\n   ebt_do_table+0xedf/0x22b0\n  Allocated by task 90:\n   __kmalloc_noprof+0x186/0x470\n   ops_init+0x6d/0x420\n   register_pernet_operations+0x2f6/0x670\n   register_pernet_subsys+0x23/0x40\n  Freed by task 93:\n   kfree+0x131/0x3c0\n   ops_undo_list+0x3e3/0x700\n   unregister_pernet_operations+0x232/0x490\n   unregister_pernet_subsys+0x1c/0x30\n   nfnetlink_log_fini+0x34/0x450 [nfnetlink_log]\n\nAcquire the ULOG logger module reference when an ebt_nflog rule is\nvalidated and release it when the rule is destroyed.  Request the NFLOG\nbackend for legacy callers when needed, matching xt_NFLOG.  This prevents\nmodule teardown until all ebt_nflog rules have stopped using the logger."
    },
    {
      "lang": "es",
      "value": "En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta:\n\nnetfilter: ebt_nflog: fijar el backend de NFLOG\n\nnf_log_unregister() se ejecuta despu\u00e9s del desmantelamiento por red, por lo que su per\u00edodo de gracia RCU final tambi\u00e9n drena a los lectores que obtuvieron el registrador de una vinculaci\u00f3n por red. Sin embargo, ebt_nflog pasa un tipo de registro ULOG expl\u00edcito a nf_log_packet() sin mantener una referencia en el m\u00f3dulo de registrador seleccionado, a diferencia de los frontends xt_NFLOG y nft_log.\n\nUna regla nflog de ebtables puede, por lo tanto, permanecer invocable mientras nfnetlink_log est\u00e1 descargado. El entrelazado resultante es:\n\n  CPU 0                               CPU 1\n  nfnetlink_log_fini()\n    unregister_pernet_subsys()\n      kfree(nfnl_log_pernet(net))\n                                      ebt_nflog_tg()\n                                        nf_log_packet()\n                                          nfulnl_log_packet()\n                                            instance_lookup_get_rcu()\n\nEl registrador ULOG global todav\u00eda est\u00e1 registrado en este punto, por lo que la CPU 1 desreferencia el estado por red despu\u00e9s de que la CPU 0 lo haya liberado. KASAN inform\u00f3:\n\n  ERROR: KASAN: uso despu\u00e9s de liberaci\u00f3n de slab en instance_lookup_get_rcu\n  Lectura de tama\u00f1o 8 en la direcci\u00f3n ff110001052e6210 por la tarea PoC/92\n  Rastro de Llamada:\n   instance_lookup_get_rcu+0x1ce/0x1f0 [nfnetlink_log]\n   nfulnl_log_packet+0x248/0x2fb0 [nfnetlink_log]\n   nf_log_packet+0x204/0x300\n   ebt_nflog_tg+0x351/0x550\n   ebt_do_table+0xedf/0x22b0\n  Asignado por la tarea 90:\n   __kmalloc_noprof+0x186/0x470\n   ops_init+0x6d/0x420\n   register_pernet_operations+0x2f6/0x670\n   register_pernet_subsys+0x23/0x40\n  Liberado por la tarea 93:\n   kfree+0x131/0x3c0\n   ops_undo_list+0x3e3/0x700\n   unregister_pernet_operations+0x232/0x490\n   unregister_pernet_subsys+0x1c/0x30\n   nfnetlink_log_fini+0x34/0x450 [nfnetlink_log]\n\nAdquirir la referencia del m\u00f3dulo de registrador ULOG cuando una regla ebt_nflog es validada y liberarla cuando la regla es destruida. Solicitar el backend de NFLOG para llamadores heredados cuando sea necesario, coincidiendo con xt_NFLOG. Esto evita el desmantelamiento del m\u00f3dulo hasta que todas las reglas ebt_nflog hayan dejado de usar el registrador."
    }
  ],
  "id": "CVE-2026-74660",
  "lastModified": "2026-10-14T13:10:00.187",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "LOCAL",
          "availabilityImpact": "HIGH",
          "baseScore": 7.8,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 1.8,
        "impactScore": 5.9,
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-08-22T16:16:39.743",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/2cac4294f184c9bc19ff82552c62b80498694c39"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/30825970339c107bacaf7f61af90fcdb1f597ca1"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/394d7939c6b2b9e6bea0844c89efb5913168d898"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/3bcce49d617c593c7606083bfdb464a1761fa68d"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/47a119ec8a7e2d5c8c4e86fb1a56c4e696e500fb"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/6809379a860b9fccbb5435bf08343f6d081ac68d"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/9d8a94b48b393885e7f876c8ef68ed4da5012078"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/e2ab7e878bdbe80104c879c31fd2d82a476703b8"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}



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