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CVE-2026-68186

Estado: RecibidaSin puntuar—

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

binfmt_misc: set have_execfd only once the interpreter is opened

load_misc_binary() raises bprm->have_execfd as soon as it sees the 'O' (or 'C') flag. This happens well before it opens the interpreter. If that open fails the flag stays set on the bprm. binfmt_misc is at the head of the format list so an interpreter open failure that returns -ENOEXEC lets the search fall through to a later format. This means it runs the matched binary directly having never staged an interpreter. So bprm->executable is NULL while have_execfd falsely claims a descriptor is present.

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Consequently, begin_new_exec() dereferences the missing executable:

and NULL derefs. Had it not, the hand-off later in the same function would have failed anyway. FD_ADD(0, bprm->executable) rejects a NULL file with -ENOMEM. Both sites are past the point of no return so the exec cannot be unwound either way.

This can be reached by unprivileged users as binfmt_misc can be mounted in user namespaces. So a user can register an 'O' entry whose interpreter lives on a FUSE mount, have the FUSE server fail the open with -ENOEXEC and execute a native ELF file that matches the entry.

have_execfd only means anything alongside the executable it describes which is not set until the interpreter has been opened and staged. So lets raise it there, next to execfd_creds, which is already set at that point. An open failure now leaves it clear, so the fallback format derives credentials from the binary and emits no AT_EXECFD, as it would for any native exec. The argv rewrite load_misc_binary() performs before the open is still not undone. This means the binary sees the interpreter path in argv[0] and its own path in argv[1] but that predates this change and only became observable once the exec stopped faulting.

Detalles técnicos trazas, registros y código del informe original
  would_dump(bprm, bprm->executable);

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-2026-68186",
  "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": "bc2bf338d54b7aadaed49bb45b9e10d4592b2a46",
              "lessThan": "a8e9e9450df44e9dd529ec5beff283f48f4f4b97",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "bc2bf338d54b7aadaed49bb45b9e10d4592b2a46",
              "lessThan": "a261dc49d99681c9c71f38d16e31812dc3e30412",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "bc2bf338d54b7aadaed49bb45b9e10d4592b2a46",
              "lessThan": "40c09b7a1d4e0a4866042c87c2bd911bb57566c8",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "bc2bf338d54b7aadaed49bb45b9e10d4592b2a46",
              "lessThan": "0f19d54e2524f0bf183b82f365ae4e49b4a2f788",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "bc2bf338d54b7aadaed49bb45b9e10d4592b2a46",
              "lessThan": "2dd0298905e97795a9c5ec30cf5b41975f821632",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "bc2bf338d54b7aadaed49bb45b9e10d4592b2a46",
              "lessThan": "1cd4e9b7967dab48c9f79a00b06ffff7208c0993",
              "versionType": "git"
            },
            {
              "status": "affected",
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              "versionType": "git"
            },
            {
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              "lessThan": "bbf5f639918dc011aaf60aab8480218758ee68c5",
              "versionType": "git"
            }
          ],
          "programFiles": [
            "fs/binfmt_misc.c"
          ],
          "defaultStatus": "unaffected"
        },
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.8"
            },
            {
              "status": "unaffected",
              "version": "0",
              "lessThan": "5.8",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "5.10.265",
              "versionType": "semver",
              "lessThanOrEqual": "5.10.*"
            },
            {
              "status": "unaffected",
              "version": "5.15.216",
              "versionType": "semver",
              "lessThanOrEqual": "5.15.*"
            },
            {
              "status": "unaffected",
              "version": "6.1.183",
              "versionType": "semver",
              "lessThanOrEqual": "6.1.*"
            },
            {
              "status": "unaffected",
              "version": "6.6.148",
              "versionType": "semver",
              "lessThanOrEqual": "6.6.*"
            },
            {
              "status": "unaffected",
              "version": "6.12.101",
              "versionType": "semver",
              "lessThanOrEqual": "6.12.*"
            },
            {
              "status": "unaffected",
              "version": "6.18.42",
              "versionType": "semver",
              "lessThanOrEqual": "6.18.*"
            },
            {
              "status": "unaffected",
              "version": "7.1.6",
              "versionType": "semver",
              "lessThanOrEqual": "7.1.*"
            },
            {
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ],
          "programFiles": [
            "fs/binfmt_misc.c"
          ],
          "defaultStatus": "affected"
        }
      ]
    }
  ],
  "published": "2026-08-10T13:20:05.740",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/0f19d54e2524f0bf183b82f365ae4e49b4a2f788",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/1cd4e9b7967dab48c9f79a00b06ffff7208c0993",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/2dd0298905e97795a9c5ec30cf5b41975f821632",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/40c09b7a1d4e0a4866042c87c2bd911bb57566c8",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/5ccc99d58f94fad258c9c375715b3974e48620e8",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/a261dc49d99681c9c71f38d16e31812dc3e30412",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/a8e9e9450df44e9dd529ec5beff283f48f4f4b97",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/bbf5f639918dc011aaf60aab8480218758ee68c5",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Received",
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbinfmt_misc: set have_execfd only once the interpreter is opened\n\nload_misc_binary() raises bprm->have_execfd as soon as it sees the 'O'\n(or 'C') flag. This happens well before it opens the interpreter. If\nthat open fails the flag stays set on the bprm. binfmt_misc is at the\nhead of the format list so an interpreter open failure that returns\n-ENOEXEC lets the search fall through to a later format. This means it\nruns the matched binary directly having never staged an interpreter. So\nbprm->executable is NULL while have_execfd falsely claims a descriptor\nis present.\n\nConsequently, begin_new_exec() dereferences the missing executable:\n\n  would_dump(bprm, bprm->executable);\n\nand NULL derefs. Had it not, the hand-off later in the same function\nwould have failed anyway. FD_ADD(0, bprm->executable) rejects a NULL\nfile with -ENOMEM. Both sites are past the point of no return so the\nexec cannot be unwound either way.\n\nThis can be reached by unprivileged users as binfmt_misc can be mounted\nin user namespaces. So a user can register an 'O' entry whose\ninterpreter lives on a FUSE mount, have the FUSE server fail the open\nwith -ENOEXEC and execute a native ELF file that matches the entry.\n\nhave_execfd only means anything alongside the executable it describes\nwhich is not set until the interpreter has been opened and staged.\nSo lets raise it there, next to execfd_creds, which is already set at\nthat point. An open failure now leaves it clear, so the fallback format\nderives credentials from the binary and emits no AT_EXECFD, as it would\nfor any native exec. The argv rewrite load_misc_binary() performs before\nthe open is still not undone. This means the binary sees the interpreter\npath in argv[0] and its own path in argv[1] but that predates this\nchange and only became observable once the exec stopped faulting."
    }
  ],
  "lastModified": "2026-08-19T17:20:34.727",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}