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CVE-2026-74740

Estado: RecibidaSin puntuar—

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

net/sched: act_api: fix TOCTOU NULL deref on a->goto_chain

tcf_action_exec() handles TC_ACT_GOTO_CHAIN by first checking rcu_access_pointer(a->goto_chain) and then calling tcf_action_goto_chain_exec(), which does a second, independent rcu_dereference_bh(a->goto_chain) read and immediately dereferences chain->filter_chain. A concurrent tcf_action_set_ctrlact() (e.g. the gact replace path) can clear a->goto_chain between the two reads, so the second read returns NULL and tcf_action_goto_chain_exec() dereferences NULL.

Fix the race by doing a single rcu_dereference_bh() read of a->goto_chain in tcf_action_exec(), checking it once for NULL, and passing the resulting chain pointer into tcf_action_goto_chain_exec().

Leer descripción completaMostrar menos

This turns the split check/use into a single check/use on one value.

CVSS

NVD no ha asignado puntuación CVSS a esta CVE (habitual desde el cambio de política de abril de 2026).

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).

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)

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{
  "id": "CVE-2026-74740",
  "cveTags": [],
  "metrics": {},
  "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": "ee3bbfe806cdb46b02cda63626cb50a7a7b19fc5",
              "lessThan": "91d55fd1fdb85c8371ca8793c788ea7d5192383a",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "ee3bbfe806cdb46b02cda63626cb50a7a7b19fc5",
              "lessThan": "1ec48b6715c29b20105e3485206602cff6c51ae5",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "ee3bbfe806cdb46b02cda63626cb50a7a7b19fc5",
              "lessThan": "abceabc4408fca6a9dd52611f5d197dec9390d63",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "ee3bbfe806cdb46b02cda63626cb50a7a7b19fc5",
              "lessThan": "6b70886ebc428eed43a069c8944a931b5fb3f4e4",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "ee3bbfe806cdb46b02cda63626cb50a7a7b19fc5",
              "lessThan": "f60b396ee174206fe08ebf997d16cd3801b77b22",
              "versionType": "git"
            }
          ],
          "programFiles": [
            "net/sched/act_api.c"
          ],
          "defaultStatus": "unaffected"
        },
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.1"
            },
            {
              "status": "unaffected",
              "version": "0",
              "lessThan": "5.1",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "6.6.153",
              "versionType": "semver",
              "lessThanOrEqual": "6.6.*"
            },
            {
              "status": "unaffected",
              "version": "6.12.105",
              "versionType": "semver",
              "lessThanOrEqual": "6.12.*"
            },
            {
              "status": "unaffected",
              "version": "6.18.46",
              "versionType": "semver",
              "lessThanOrEqual": "6.18.*"
            },
            {
              "status": "unaffected",
              "version": "7.1.10",
              "versionType": "semver",
              "lessThanOrEqual": "7.1.*"
            },
            {
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ],
          "programFiles": [
            "net/sched/act_api.c"
          ],
          "defaultStatus": "affected"
        }
      ]
    }
  ],
  "published": "2026-08-26T15:16:52.743",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/1ec48b6715c29b20105e3485206602cff6c51ae5",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/6b70886ebc428eed43a069c8944a931b5fb3f4e4",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/91d55fd1fdb85c8371ca8793c788ea7d5192383a",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/abceabc4408fca6a9dd52611f5d197dec9390d63",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/f60b396ee174206fe08ebf997d16cd3801b77b22",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Received",
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: act_api: fix TOCTOU NULL deref on a->goto_chain\n\ntcf_action_exec() handles TC_ACT_GOTO_CHAIN by first checking\nrcu_access_pointer(a->goto_chain) and then calling\ntcf_action_goto_chain_exec(), which does a second, independent\nrcu_dereference_bh(a->goto_chain) read and immediately dereferences\nchain->filter_chain. A concurrent tcf_action_set_ctrlact() (e.g. the gact\nreplace path) can clear a->goto_chain between the two reads, so the second\nread returns NULL and tcf_action_goto_chain_exec() dereferences NULL.\n\nFix the race by doing a single rcu_dereference_bh() read of a->goto_chain\nin tcf_action_exec(), checking it once for NULL, and passing the resulting\nchain pointer into tcf_action_goto_chain_exec(). This turns the split\ncheck/use into a single check/use on one value."
    }
  ],
  "lastModified": "2026-08-26T15:16:52.743",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}