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CVE-2025-40206

Estado: AplazadaAlta (7.8)—

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

netfilter: nft_objref: validate objref and objrefmap expressions

Referencing a synproxy stateful object from OUTPUT hook causes kernel crash due to infinite recursive calls:

Implement objref and objrefmap expression validate functions.

Currently, only NFT_OBJECT_SYNPROXY object type requires validation. This will also handle a jump to a chain using a synproxy object from the OUTPUT hook.

Now when trying to reference a synproxy object in the OUTPUT hook, nft will produce the following error:

Detalles técnicos trazas, registros y código del informe original
BUG: TASK stack guard page was hit at 000000008bda5b8c (stack is 000000003ab1c4a5..00000000494d8b12)
[...]
Call Trace:
 __find_rr_leaf+0x99/0x230
 fib6_table_lookup+0x13b/0x2d0
 ip6_pol_route+0xa4/0x400
 fib6_rule_lookup+0x156/0x240
 ip6_route_output_flags+0xc6/0x150
 __nf_ip6_route+0x23/0x50
 synproxy_send_tcp_ipv6+0x106/0x200
 synproxy_send_client_synack_ipv6+0x1aa/0x1f0
 nft_synproxy_do_eval+0x263/0x310
 nft_do_chain+0x5a8/0x5f0 [nf_tables
 nft_do_chain_inet+0x98/0x110
 nf_hook_slow+0x43/0xc0
 __ip6_local_out+0xf0/0x170
 ip6_local_out+0x17/0x70
 synproxy_send_tcp_ipv6+0x1a2/0x200
 synproxy_send_client_synack_ipv6+0x1aa/0x1f0
[...]

synproxy_crash.nft: Error: Could not process rule: Operation not supported
  synproxy name mysynproxy
  ^^^^^^^^^^^^^^^^^^^^^^^^

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 local con PR:L que causa crash del kernel (DoS) por recursión infinita en netfilter al referenciar objetos synproxy desde OUTPUT hook.

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

Tecnologías afectadas (1)

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

Referencias

JSON original (NVD)

Mostrar
{
  "id": "CVE-2025-40206",
  "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": "ee394f96ad7517fbc0de9106dcc7ce9efb14f264",
              "lessThan": "f31bcea12222a26d6f151df9c4a6d21f2eec1724",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "ee394f96ad7517fbc0de9106dcc7ce9efb14f264",
              "lessThan": "0028e0134c64d9ed21728341a74fcfc59cd0f944",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "ee394f96ad7517fbc0de9106dcc7ce9efb14f264",
              "lessThan": "7ea55a44493a5a36c3b3293b88bbe4841f9dbaf0",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "ee394f96ad7517fbc0de9106dcc7ce9efb14f264",
              "lessThan": "4c1cf72ec10be5a9ad264650cadffa1fbce6fabd",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "ee394f96ad7517fbc0de9106dcc7ce9efb14f264",
              "lessThan": "f359b809d54c6e3dd1d039b97e0b68390b0e53e4",
              "versionType": "git"
            }
          ],
          "programFiles": [
            "net/netfilter/nft_objref.c"
          ],
          "defaultStatus": "unaffected"
        },
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.4"
            },
            {
              "status": "unaffected",
              "version": "0",
              "lessThan": "5.4",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "6.1.184",
              "versionType": "semver",
              "lessThanOrEqual": "6.1.*"
            },
            {
              "status": "unaffected",
              "version": "6.6.113",
              "versionType": "semver",
              "lessThanOrEqual": "6.6.*"
            },
            {
              "status": "unaffected",
              "version": "6.12.54",
              "versionType": "semver",
              "lessThanOrEqual": "6.12.*"
            },
            {
              "status": "unaffected",
              "version": "6.17.4",
              "versionType": "semver",
              "lessThanOrEqual": "6.17.*"
            },
            {
              "status": "unaffected",
              "version": "6.18",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ],
          "programFiles": [
            "net/netfilter/nft_objref.c"
          ],
          "defaultStatus": "affected"
        }
      ]
    }
  ],
  "published": "2025-11-12T22:15:47.893",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/0028e0134c64d9ed21728341a74fcfc59cd0f944",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/4c1cf72ec10be5a9ad264650cadffa1fbce6fabd",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/7ea55a44493a5a36c3b3293b88bbe4841f9dbaf0",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/f31bcea12222a26d6f151df9c4a6d21f2eec1724",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/f359b809d54c6e3dd1d039b97e0b68390b0e53e4",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Deferred",
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: nft_objref: validate objref and objrefmap expressions\n\nReferencing a synproxy stateful object from OUTPUT hook causes kernel\ncrash due to infinite recursive calls:\n\nBUG: TASK stack guard page was hit at 000000008bda5b8c (stack is 000000003ab1c4a5..00000000494d8b12)\n[...]\nCall Trace:\n __find_rr_leaf+0x99/0x230\n fib6_table_lookup+0x13b/0x2d0\n ip6_pol_route+0xa4/0x400\n fib6_rule_lookup+0x156/0x240\n ip6_route_output_flags+0xc6/0x150\n __nf_ip6_route+0x23/0x50\n synproxy_send_tcp_ipv6+0x106/0x200\n synproxy_send_client_synack_ipv6+0x1aa/0x1f0\n nft_synproxy_do_eval+0x263/0x310\n nft_do_chain+0x5a8/0x5f0 [nf_tables\n nft_do_chain_inet+0x98/0x110\n nf_hook_slow+0x43/0xc0\n __ip6_local_out+0xf0/0x170\n ip6_local_out+0x17/0x70\n synproxy_send_tcp_ipv6+0x1a2/0x200\n synproxy_send_client_synack_ipv6+0x1aa/0x1f0\n[...]\n\nImplement objref and objrefmap expression validate functions.\n\nCurrently, only NFT_OBJECT_SYNPROXY object type requires validation.\nThis will also handle a jump to a chain using a synproxy object from the\nOUTPUT hook.\n\nNow when trying to reference a synproxy object in the OUTPUT hook, nft\nwill produce the following error:\n\nsynproxy_crash.nft: Error: Could not process rule: Operation not supported\n  synproxy name mysynproxy\n  ^^^^^^^^^^^^^^^^^^^^^^^^"
    }
  ],
  "lastModified": "2026-08-23T13:16:26.737",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}