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CVE-2023-54243

Estado: AplazadaAlta (7.8)—

In the Linux kernel, the following vulnerability has been resolved:

netfilter: ebtables: fix table blob use-after-free

We are not allowed to return an error at this point. Looking at the code it looks like ret is always 0 at this point, but its not.

... this can return a valid table, with ret != 0.

This bug causes update of table->private with the new blob, but then frees the blob right away in the caller.

Syzbot report:

ip(6)tables appears to be ok (ret should be 0 at this point) but make this more obvious.

Detalles técnicos trazas, registros y código del informe original
t = find_table_lock(net, repl->name, &ret, &ebt_mutex);

BUG: KASAN: vmalloc-out-of-bounds in __ebt_unregister_table+0xc00/0xcd0 net/bridge/netfilter/ebtables.c:1168
Read of size 4 at addr ffffc90005425000 by task kworker/u4:4/74
Workqueue: netns cleanup_net
Call Trace:
 kasan_report+0xbf/0x1f0 mm/kasan/report.c:517
 __ebt_unregister_table+0xc00/0xcd0 net/bridge/netfilter/ebtables.c:1168
 ebt_unregister_table+0x35/0x40 net/bridge/netfilter/ebtables.c:1372
 ops_exit_list+0xb0/0x170 net/core/net_namespace.c:169
 cleanup_net+0x4ee/0xb10 net/core/net_namespace.c:613
...

CVSS

Probabilidad de explotación (EPSS)

EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).

🎯 Técnicas ATT&CK

Cómo se explota esta vulnerabilidad y qué consigue el atacante, en el lenguaje de MITRE ATT&CK.

Vulnerabilidad de use-after-free (CWE-416) en netfilter con AV:L/PR:L: escalada local. Impacto: negación de servicio (crash del kernel) y corrupción de memoria.

Inferido por nuestro agente de análisis a partir de la descripción oficial, el vector CVSS y la CWE, y comprobado por un supervisor. Puede contener errores.

🛡️ Mitigaciones ATT&CK que cubren estas técnicas

Threat Intelligence ProgramFilter Network TrafficExecution PreventionApplication Isolation and SandboxingExploit ProtectionUpdate Software

Tecnologías afectadas (1)

⚠ Inferidas por IA a partir de la descripción — NVD aún no ha analizado esta CVE; no son CPE verificados.

Linux — Linux KernelAI

Referencias

JSON original (NVD)

Mostrar
{
  "id": "CVE-2023-54243",
  "cveTags": [],
  "metrics": {
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 7.8,
          "attackVector": "LOCAL",
          "baseSeverity": "HIGH",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
          "integrityImpact": "HIGH",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "confidentialityImpact": "HIGH"
        },
        "impactScore": 5.9,
        "exploitabilityScore": 1.8
      }
    ]
  },
  "affected": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "affectedData": [
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "c58dd2dd443c26d856a168db108a0cd11c285bf3",
              "lessThan": "9060abce3305ab2354c892c09d5689df51486df5",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "c58dd2dd443c26d856a168db108a0cd11c285bf3",
              "lessThan": "dbb3cbbf03b3c52cb390fabec357f1e4638004f5",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "c58dd2dd443c26d856a168db108a0cd11c285bf3",
              "lessThan": "3dd6ac973351308d4117eda32298a9f1d68764fd",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "c58dd2dd443c26d856a168db108a0cd11c285bf3",
              "lessThan": "cda0e0243bd3c04008fcd37a46b0269fb3c49249",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "c58dd2dd443c26d856a168db108a0cd11c285bf3",
              "lessThan": "e58a171d35e32e6e8c37cfe0e8a94406732a331f",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "a3bc0f8ea439762aa62d40a295157410498cbea7",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "8ed40c122919cd79bc3c059e5864e5e7d9d455f0",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "c5e4ef499cfc78de45a4f01b8c557b5964d77c53",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "f34728610b2a8c7b9864f9404f2884c17f6fca5c",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "8b5740915a9faa8b1fa9166193a33e2a9ae30ec6",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "3.2.60",
              "lessThan": "3.3",
              "versionType": "semver"
            },
            {
              "status": "affected",
              "version": "3.4.91",
              "lessThan": "3.5",
              "versionType": "semver"
            },
            {
              "status": "affected",
              "version": "3.10.41",
              "lessThan": "3.11",
              "versionType": "semver"
            },
            {
              "status": "affected",
              "version": "3.12.21",
              "lessThan": "3.13",
              "versionType": "semver"
            },
            {
              "status": "affected",
              "version": "3.14.5",
              "lessThan": "3.15",
              "versionType": "semver"
            }
          ],
          "programFiles": [
            "net/bridge/netfilter/ebtables.c",
            "net/ipv4/netfilter/ip_tables.c",
            "net/ipv6/netfilter/ip6_tables.c"
          ],
          "defaultStatus": "unaffected"
        },
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "3.15"
            },
            {
              "status": "unaffected",
              "version": "0",
              "lessThan": "3.15",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "5.10.173",
              "versionType": "semver",
              "lessThanOrEqual": "5.10.*"
            },
            {
              "status": "unaffected",
              "version": "5.15.100",
              "versionType": "semver",
              "lessThanOrEqual": "5.15.*"
            },
            {
              "status": "unaffected",
              "version": "6.1.18",
              "versionType": "semver",
              "lessThanOrEqual": "6.1.*"
            },
            {
              "status": "unaffected",
              "version": "6.2.5",
              "versionType": "semver",
              "lessThanOrEqual": "6.2.*"
            },
            {
              "status": "unaffected",
              "version": "6.3",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ],
          "programFiles": [
            "net/bridge/netfilter/ebtables.c",
            "net/ipv4/netfilter/ip_tables.c",
            "net/ipv6/netfilter/ip6_tables.c"
          ],
          "defaultStatus": "affected"
        }
      ]
    }
  ],
  "published": "2025-12-30T13:16:12.880",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/3dd6ac973351308d4117eda32298a9f1d68764fd",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/9060abce3305ab2354c892c09d5689df51486df5",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/cda0e0243bd3c04008fcd37a46b0269fb3c49249",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/dbb3cbbf03b3c52cb390fabec357f1e4638004f5",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/e58a171d35e32e6e8c37cfe0e8a94406732a331f",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Deferred",
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: ebtables: fix table blob use-after-free\n\nWe are not allowed to return an error at this point.\nLooking at the code it looks like ret is always 0 at this\npoint, but its not.\n\nt = find_table_lock(net, repl->name, &ret, &ebt_mutex);\n\n... this can return a valid table, with ret != 0.\n\nThis bug causes update of table->private with the new\nblob, but then frees the blob right away in the caller.\n\nSyzbot report:\n\nBUG: KASAN: vmalloc-out-of-bounds in __ebt_unregister_table+0xc00/0xcd0 net/bridge/netfilter/ebtables.c:1168\nRead of size 4 at addr ffffc90005425000 by task kworker/u4:4/74\nWorkqueue: netns cleanup_net\nCall Trace:\n kasan_report+0xbf/0x1f0 mm/kasan/report.c:517\n __ebt_unregister_table+0xc00/0xcd0 net/bridge/netfilter/ebtables.c:1168\n ebt_unregister_table+0x35/0x40 net/bridge/netfilter/ebtables.c:1372\n ops_exit_list+0xb0/0x170 net/core/net_namespace.c:169\n cleanup_net+0x4ee/0xb10 net/core/net_namespace.c:613\n...\n\nip(6)tables appears to be ok (ret should be 0 at this point) but make\nthis more obvious."
    },
    {
      "lang": "es",
      "value": "En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta:\n\nnetfilter: ebtables: corregir uso después de liberación de blob de tabla\n\nNo se nos permite devolver un error en este punto.\nAl mirar el código parece que ret siempre es 0 en este\npunto, pero no lo es.\n\nt = find_table_lock(net, repl->name, &ret, &ebt_mutex);\n\n... esto puede devolver una tabla válida, con ret != 0.\n\nEste error causa la actualización de table->private con el nuevo\nblob, pero luego libera el blob inmediatamente en el llamador.\n\nInforme de Syzbot:\n\nERROR: KASAN: vmalloc-fuera-de-límites en __ebt_unregister_table+0xc00/0xcd0 net/bridge/netfilter/ebtables.c:1168\nLectura de tamaño 4 en la dirección ffffc90005425000 por la tarea kworker/u4:4/74\nCola de trabajo: netns cleanup_net\nTraza de llamada:\n kasan_report+0xbf/0x1f0 mm/kasan/report.c:517\n __ebt_unregister_table+0xc00/0xcd0 net/bridge/netfilter/ebtables.c:1168\n ebt_unregister_table+0x35/0x40 net/bridge/netfilter/ebtables.c:1372\n ops_exit_list+0xb0/0x170 net/core/net_namespace.c:169\n cleanup_net+0x4ee/0xb10 net/core/net_namespace.c:613\n...\n\nip(6)tables parece estar bien (ret debería ser 0 en este punto) pero hacer\nesto más obvio."
    }
  ],
  "lastModified": "2026-08-04T11:16:38.120",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}