Vulnerability-Lookup

CVE-2026-49429 (GCVE-0-2026-49429)

Vulnerability from cvelistv5 – Published: 2026-08-19 05:15 – Updated: 2026-08-19 12:16

Title

Kernel heap overflow in ZFS_IOC_USERSPACE_MANY ioctl

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.

Severity

7.8 (High)


                        
                          CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

SSVC

Exploitation: none Automatable: no Technical Impact: total

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-08-19 12:16 UTC

CWE

CWE-122 - Heap-based Buffer Overflow

Assigner

freebsd mitre root

References

1 reference

URL	Tags
https://security.freebsd.org/advisories/FreeBSD-S…	vendor-advisory

Impacted products

1 product

Vendor	Product	Version	CPE status
FreeBSD	FreeBSD	Affected: 15.1-RELEASE , < p1 (release) Affected: 15.0-RELEASE , < p11 (release) Affected: 14.4-RELEASE , < p7 (release) Affected: 14.3-RELEASE , < p16 (release)	guessed

Date Public

2026-06-30 20:00

Credits

Yuxiang Yang, Yizhou Zhao, Ao Wang, Xuewei Feng, Qi Li, and Ke Xu from Tsinghua University using GLM-5.1 from Z.ai Emmanuel Genier at Quarkslab

Show details on NVD website

JSON

To clipboard

{
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              "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",
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            }
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                  },
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                    "Technical Impact": "total"
                  }
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                "role": "CISA Coordinator",
                "timestamp": "2026-08-19T12:16:14.445112Z",
                "version": "2.0.3"
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        "providerMetadata": {
          "dateUpdated": "2026-08-19T12:16:35.367Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
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          "modules": [
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          "product": "FreeBSD",
          "vendor": "FreeBSD",
          "versions": [
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              "status": "affected",
              "version": "15.1-RELEASE",
              "versionType": "release"
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              "versionType": "release"
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              "version": "14.3-RELEASE",
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          "type": "finder",
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        },
        {
          "lang": "en",
          "type": "finder",
          "value": "Emmanuel Genier at Quarkslab"
        }
      ],
      "datePublic": "2026-06-30T20:00:00.000Z",
      "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."
        }
      ],
      "problemTypes": [
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          "descriptions": [
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              "description": "CWE-122: Heap-based Buffer Overflow",
              "lang": "en",
              "type": "CWE"
            }
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      "providerMetadata": {
        "dateUpdated": "2026-08-19T05:15:21.198Z",
        "orgId": "63664ac6-956c-4cba-a5d0-f46076e16109",
        "shortName": "freebsd"
      },
      "references": [
        {
          "tags": [
            "vendor-advisory"
          ],
          "url": "https://security.freebsd.org/advisories/FreeBSD-SA-26:40.zfs.asc"
        }
      ],
      "title": "Kernel heap overflow in ZFS_IOC_USERSPACE_MANY ioctl",
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        "engine": "cvelib 1.8.0"
      }
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  "cveMetadata": {
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    "cveId": "CVE-2026-49429",
    "datePublished": "2026-08-19T05:15:21.198Z",
    "dateReserved": "2026-05-29T20:24:28.616Z",
    "dateUpdated": "2026-08-19T12:16:35.367Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
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      "date": "2026-08-19",
      "epss": "0.00205",
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  }
}

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

References

	URL	Tags
	secteam@freebsd.org	https://security.freebsd.org/advisories/FreeBSD-SA-26:40.zfs.asc

Impacted products

	Vendor	Product	Version

JSON

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"
            },
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              "status": "affected",
              "version": "14.3-RELEASE",
              "versionType": "release"
            }
          ]
        }
      ],
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    }
  ],
  "cveTags": [],
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    {
      "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": [
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        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
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          "options": [
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          "role": "CISA Coordinator",
          "timestamp": "2026-08-19T12:16:14.445112Z",
          "version": "2.0.3"
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  "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": [
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          "lang": "en",
          "value": "CWE-122"
        }
      ],
      "source": "secteam@freebsd.org",
      "type": "Secondary"
    }
  ]
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

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.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.

Action not permitted

CVE-2026-49429 (GCVE-0-2026-49429)

FKIE_CVE-2026-49429

Tags

Sightings

Nomenclature