FKIE_CVE-2026-49429

Vulnerability from fkie_nvd - Published: 2026-08-19 06:17 - Updated: 2026-08-19 13:17
Severity
7.8 (High) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Summary
The ZFS_IOC_USERSPACE_MANY ioctl, used by zfs-userspace(8), truncated a 64-bit output buffer size to a 32-bit integer for the kernel allocation, but used the original 64-bit size as the buffer limit when writing records. A local user with the "userused" delegated ZFS permission can trigger a kernel heap overflow via the ZFS_IOC_USERSPACE_MANY ioctl, potentially escalating privileges.
References
secteam@freebsd.orghttps://security.freebsd.org/advisories/FreeBSD-SA-26:40.zfs.asc
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unknown",
          "modules": [
            "zfs"
          ],
          "product": "FreeBSD",
          "vendor": "FreeBSD",
          "versions": [
            {
              "lessThan": "p1",
              "status": "affected",
              "version": "15.1-RELEASE",
              "versionType": "release"
            },
            {
              "lessThan": "p11",
              "status": "affected",
              "version": "15.0-RELEASE",
              "versionType": "release"
            },
            {
              "lessThan": "p7",
              "status": "affected",
              "version": "14.4-RELEASE",
              "versionType": "release"
            },
            {
              "lessThan": "p16",
              "status": "affected",
              "version": "14.3-RELEASE",
              "versionType": "release"
            }
          ]
        }
      ],
      "source": "secteam@freebsd.org"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "The ZFS_IOC_USERSPACE_MANY ioctl, used by zfs-userspace(8), truncated a 64-bit output buffer size to a 32-bit integer for the kernel allocation, but used the original 64-bit size as the buffer limit when writing records.\n\nA local user with the \"userused\" delegated ZFS permission can trigger a kernel heap overflow via the ZFS_IOC_USERSPACE_MANY ioctl, potentially escalating privileges."
    }
  ],
  "id": "CVE-2026-49429",
  "lastModified": "2026-08-19T13:17:46.030",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "LOCAL",
          "availabilityImpact": "HIGH",
          "baseScore": 7.8,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 1.8,
        "impactScore": 5.9,
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "type": "Secondary"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-49429",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "total"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-08-19T12:16:14.445112Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2026-08-19T06:17:42.513",
  "references": [
    {
      "source": "secteam@freebsd.org",
      "url": "https://security.freebsd.org/advisories/FreeBSD-SA-26:40.zfs.asc"
    }
  ],
  "sourceIdentifier": "secteam@freebsd.org",
  "vulnStatus": "Received",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-122"
        }
      ],
      "source": "secteam@freebsd.org",
      "type": "Secondary"
    }
  ]
}



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