FKIE_CVE-2026-74689

Vulnerability from fkie_nvd - Published: 2026-08-22 16:16 - Updated: 2026-10-14 13:10
Severity
7.1 (High) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: net/atm: fix slab-out-of-bounds read in vcc_setsockopt() vcc_setsockopt() contained an ineffective optlen check: if (__SO_LEVEL_MATCH(optname, level) && optlen != __SO_SIZE(optname)) return -EINVAL; If __SO_LEVEL_MATCH(optname, level) evaluated to false (e.g. if the caller passed a mismatched level), the length check optlen != __SO_SIZE(optname) was short-circuited and bypassed. Execution then fell through to switch(optname), calling copy_from_sockptr() assuming optval contained sufficient space. Furthermore, even if level matched, a cgroup BPF setsockopt filter could shrink optlen after entry. Because copy_from_sockptr() on kernel pointers uses memcpy(), this leads to a KASAN slab-out-of-bounds read when optlen is smaller than the expected structure size. Fix this by using copy_safe_from_sockptr(), which unconditionally validates that optlen is at least the expected size before copying. Also change the local 'value' variable type from 'unsigned long' to 'int' so that SO_SETCLP matches its sizeof(int) ABI encoding on 64-bit systems.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/2c5988c7349c0b64a7e0441bfc6e1dca54f7116a
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/35f258fee9ed358c6d0f57f91c30bf029c3724af
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/6eb6af88710977eb529b558a07294874d8c40c4d
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/9f77c1ab382188f5b51982fab6d913443b6dc59f
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/b3bcd5d65ac03c15787b2a5b36c718e26a689336
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/d0c80dbb970439bd2eeb0e5effff8c16a5f4e1e3
Impacted products
Vendor Product Version
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{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/atm/common.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "b3bcd5d65ac03c15787b2a5b36c718e26a689336",
              "status": "affected",
              "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
              "versionType": "git"
            },
            {
              "lessThan": "35f258fee9ed358c6d0f57f91c30bf029c3724af",
              "status": "affected",
              "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
              "versionType": "git"
            },
            {
              "lessThan": "6eb6af88710977eb529b558a07294874d8c40c4d",
              "status": "affected",
              "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
              "versionType": "git"
            },
            {
              "lessThan": "9f77c1ab382188f5b51982fab6d913443b6dc59f",
              "status": "affected",
              "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
              "versionType": "git"
            },
            {
              "lessThan": "2c5988c7349c0b64a7e0441bfc6e1dca54f7116a",
              "status": "affected",
              "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
              "versionType": "git"
            },
            {
              "lessThan": "d0c80dbb970439bd2eeb0e5effff8c16a5f4e1e3",
              "status": "affected",
              "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "net/atm/common.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "2.6.12"
            },
            {
              "lessThan": "2.6.12",
              "status": "unaffected",
              "version": "0",
              "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\nnet/atm: fix slab-out-of-bounds read in vcc_setsockopt()\n\nvcc_setsockopt() contained an ineffective optlen check:\n  if (__SO_LEVEL_MATCH(optname, level) \u0026\u0026 optlen != __SO_SIZE(optname))\n      return -EINVAL;\n\nIf __SO_LEVEL_MATCH(optname, level) evaluated to false (e.g. if the caller\npassed a mismatched level), the length check optlen != __SO_SIZE(optname)\nwas short-circuited and bypassed. Execution then fell through to switch(optname),\ncalling copy_from_sockptr() assuming optval contained sufficient space.\n\nFurthermore, even if level matched, a cgroup BPF setsockopt filter could shrink\noptlen after entry. Because copy_from_sockptr() on kernel pointers uses memcpy(),\nthis leads to a KASAN slab-out-of-bounds read when optlen is smaller than the\nexpected structure size.\n\nFix this by using copy_safe_from_sockptr(), which unconditionally validates\nthat optlen is at least the expected size before copying. Also change the local\n\u0027value\u0027 variable type from \u0027unsigned long\u0027 to \u0027int\u0027 so that SO_SETCLP matches\nits sizeof(int) ABI encoding on 64-bit systems."
    },
    {
      "lang": "es",
      "value": "En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta:\n\nnet/atm: corrige lectura fuera de l\u00edmites de slab en vcc_setsockopt()\n\nvcc_setsockopt() conten\u00eda una comprobaci\u00f3n de optlen ineficaz:\n  if (__SO_LEVEL_MATCH(optname, level) \u0026\u0026 optlen != __SO_SIZE(optname))\n      return -EINVAL;\n\nSi __SO_LEVEL_MATCH(optname, level) evaluaba a falso (por ejemplo, si el llamador pasaba un nivel no coincidente), la comprobaci\u00f3n de longitud optlen != __SO_SIZE(optname) era cortocircuitada y omitida. La ejecuci\u00f3n entonces pasaba a switch(optname), llamando a copy_from_sockptr() asumiendo que optval conten\u00eda espacio suficiente.\n\nAdem\u00e1s, incluso si el nivel coincid\u00eda, un filtro setsockopt de cgroup BPF podr\u00eda reducir optlen despu\u00e9s de la entrada. Debido a que copy_from_sockptr() en punteros de kernel usa memcpy(), esto lleva a una lectura fuera de l\u00edmites de slab de KASAN cuando optlen es menor que el tama\u00f1o de estructura esperado.\n\nSolucione esto usando copy_safe_from_sockptr(), que valida incondicionalmente que optlen tiene al menos el tama\u00f1o esperado antes de copiar. Tambi\u00e9n cambie el tipo de la variable local \u0027value\u0027 de \u0027unsigned long\u0027 a \u0027int\u0027 para que SO_SETCLP coincida con su codificaci\u00f3n ABI sizeof(int) en sistemas de 64 bits."
    }
  ],
  "id": "CVE-2026-74689",
  "lastModified": "2026-10-14T13:10:00.187",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "LOCAL",
          "availabilityImpact": "HIGH",
          "baseScore": 7.1,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "NONE",
          "privilegesRequired": "LOW",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 1.8,
        "impactScore": 5.2,
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-08-22T16:16:43.303",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/2c5988c7349c0b64a7e0441bfc6e1dca54f7116a"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/35f258fee9ed358c6d0f57f91c30bf029c3724af"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/6eb6af88710977eb529b558a07294874d8c40c4d"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/9f77c1ab382188f5b51982fab6d913443b6dc59f"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/b3bcd5d65ac03c15787b2a5b36c718e26a689336"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/d0c80dbb970439bd2eeb0e5effff8c16a5f4e1e3"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}



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