FKIE_CVE-2026-49429

Vulnerability from fkie_nvd - Published: 2026-08-19 06:17 - Updated: 2026-09-01 20:05
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.ascVendor Advisory
Impacted products
Vendor Product Version
freebsd freebsd 14.3
freebsd freebsd 14.3
freebsd freebsd 14.3
freebsd freebsd 14.3
freebsd freebsd 14.3
freebsd freebsd 14.3
freebsd freebsd 14.3
freebsd freebsd 14.3
freebsd freebsd 14.3
freebsd freebsd 14.3
freebsd freebsd 14.3
freebsd freebsd 14.3
freebsd freebsd 14.3
freebsd freebsd 14.3
freebsd freebsd 14.3
freebsd freebsd 14.3
freebsd freebsd 14.4
freebsd freebsd 14.4
freebsd freebsd 14.4
freebsd freebsd 14.4
freebsd freebsd 14.4
freebsd freebsd 14.4
freebsd freebsd 14.4
freebsd freebsd 14.4
freebsd freebsd 15.0
freebsd freebsd 15.0
freebsd freebsd 15.0
freebsd freebsd 15.0
freebsd freebsd 15.0
freebsd freebsd 15.0
freebsd freebsd 15.0
freebsd freebsd 15.0
freebsd freebsd 15.0
freebsd freebsd 15.0
freebsd freebsd 15.0
freebsd freebsd 15.1
freebsd freebsd 15.1
freebsd freebsd 15.1
To clipboard 

{
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          "modules": [
            "zfs"
          ],
          "product": "FreeBSD",
          "vendor": "FreeBSD",
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              "version": "14.3-RELEASE",
              "versionType": "release"
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      ],
      "source": "secteam@freebsd.org"
    }
  ],
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  ],
  "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": "2026-09-01T20:05:50.613",
  "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": "2026-08-19T00:00:00+00:00",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2026-08-19T06:17:42.513",
  "references": [
    {
      "source": "secteam@freebsd.org",
      "tags": [
        "Vendor Advisory"
      ],
      "url": "https://security.freebsd.org/advisories/FreeBSD-SA-26:40.zfs.asc"
    }
  ],
  "sourceIdentifier": "secteam@freebsd.org",
  "vulnStatus": "Analyzed",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-122"
        }
      ],
      "source": "secteam@freebsd.org",
      "type": "Secondary"
    }
  ]
}



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  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
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