Vulnerability-Lookup

FKIE_CVE-2026-7007

Vulnerability from fkie_nvd - Published: 2026-07-24 15:19 - Updated: 2026-09-01 00:16

Severity

4.6 (Medium) - CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Summary

The Zephyr ext2 file system validates the on-disk superblock in ext2_verify_disk_superblock() (subsys/fs/ext2/ext2_impl.c) before completing a mount. The validator checked the magic number, block size, revision and feature flags, but did not verify that the on-disk fields s_blocks_per_group and s_inodes_per_group are non-zero. Both fields are read directly from the image and are later used as divisors during mount-time initialization. During mount, get_ngroups() divides and modulos s_blocks_count by s_blocks_per_group (reached via ext2_fetch_block_group() from ext2_init_fs()), and get_itable_entry() divides (ino - 1) by s_inodes_per_group when fetching the root inode (both in subsys/fs/ext2/ext2_diskops.c). A superblock with either field set to zero therefore causes an integer division by zero during the mount sequence. An attacker who can present a crafted ext2 image to a device that mounts ext2 — removable media such as an SD card or a USB mass-storage device — can trigger this. On ARMv7-M / ARMv8-M-mainline Cortex-M targets, divide-by-zero trapping is enabled (SCB_CCR_DIV_0_TRP), so the division raises a UsageFault that Zephyr treats as a fatal error, producing a denial of service. The impact is limited to availability; the malformed value is consumed only as a divisor. The fix rejects a zero s_blocks_per_group or s_inodes_per_group in the superblock validator, returning -EINVAL so the mount fails before any block-group or inode I/O occurs.

References

	URL	Tags
	vulnerabilities@zephyrproject.org	https://github.com/zephyrproject-rtos/zephyr/commit/babc0900ed40e6c023ccc26aa1a321f9388b66af	Patch
	vulnerabilities@zephyrproject.org	https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-wrf2-79mm-cvw5	Exploit, Patch, Vendor Advisory

Impacted products

	Vendor	Product	Version
	zephyrproject	zephyr	*

JSON

To clipboard

{
  "affected": [
    {
      "affectedData": [
        {
          "collectionURL": "https://github.com/zephyrproject-rtos/zephyr",
          "defaultStatus": "unaffected",
          "packageName": "zephyr",
          "product": "zephyr",
          "programFiles": [
            "subsys/fs/ext2/ext2_impl.c"
          ],
          "vendor": "zephyrproject",
          "versions": [
            {
              "lessThan": "4.4.2",
              "status": "affected",
              "version": "3.5.0",
              "versionType": "semver"
            }
          ]
        }
      ],
      "source": "vulnerabilities@zephyrproject.org"
    }
  ],
  "configurations": [
    {
      "nodes": [
        {
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:o:zephyrproject:zephyr:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "7F70CCFD-FCBB-436A-9E01-D8AAB9948497",
              "versionEndExcluding": "4.5.0",
              "versionStartIncluding": "3.5.0",
              "vulnerable": true
            }
          ],
          "negate": false,
          "operator": "OR"
        }
      ]
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "The Zephyr ext2 file system validates the on-disk superblock in ext2_verify_disk_superblock() (subsys/fs/ext2/ext2_impl.c) before completing a mount. The validator checked the magic number, block size, revision and feature flags, but did not verify that the on-disk fields s_blocks_per_group and s_inodes_per_group are non-zero. Both fields are read directly from the image and are later used as divisors during mount-time initialization.\n\nDuring mount, get_ngroups() divides and modulos s_blocks_count by s_blocks_per_group (reached via ext2_fetch_block_group() from ext2_init_fs()), and get_itable_entry() divides (ino - 1) by s_inodes_per_group when fetching the root inode (both in subsys/fs/ext2/ext2_diskops.c). A superblock with either field set to zero therefore causes an integer division by zero during the mount sequence.\n\nAn attacker who can present a crafted ext2 image to a device that mounts ext2 \u2014 removable media such as an SD card or a USB mass-storage device \u2014 can trigger this. On ARMv7-M / ARMv8-M-mainline Cortex-M targets, divide-by-zero trapping is enabled (SCB_CCR_DIV_0_TRP), so the division raises a UsageFault that Zephyr treats as a fatal error, producing a denial of service. The impact is limited to availability; the malformed value is consumed only as a divisor.\n\nThe fix rejects a zero s_blocks_per_group or s_inodes_per_group in the superblock validator, returning -EINVAL so the mount fails before any block-group or inode I/O occurs."
    }
  ],
  "id": "CVE-2026-7007",
  "lastModified": "2026-09-01T00:16:43.640",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "PHYSICAL",
          "availabilityImpact": "HIGH",
          "baseScore": 4.6,
          "baseSeverity": "MEDIUM",
          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 0.9,
        "impactScore": 3.6,
        "source": "vulnerabilities@zephyrproject.org",
        "type": "Secondary"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-7007",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-07-24T15:03:26.497157Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2026-07-24T15:19:08.047",
  "references": [
    {
      "source": "vulnerabilities@zephyrproject.org",
      "tags": [
        "Patch"
      ],
      "url": "https://github.com/zephyrproject-rtos/zephyr/commit/babc0900ed40e6c023ccc26aa1a321f9388b66af"
    },
    {
      "source": "vulnerabilities@zephyrproject.org",
      "tags": [
        "Exploit",
        "Patch",
        "Vendor Advisory"
      ],
      "url": "https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-wrf2-79mm-cvw5"
    }
  ],
  "sourceIdentifier": "vulnerabilities@zephyrproject.org",
  "vulnStatus": "Analyzed",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-369"
        }
      ],
      "source": "vulnerabilities@zephyrproject.org",
      "type": "Secondary"
    },
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-369"
        }
      ],
      "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
      "type": "Secondary"
    }
  ]
}

CVE-2026-7007 (GCVE-0-2026-7007)

Vulnerability from cvelistv5 – Published: 2026-07-24 13:48 – Updated: 2026-08-31 23:13

Title

Division by zero in Zephyr ext2 superblock parsing allows DoS via crafted filesystem image

Summary

Severity

4.6 (Medium)


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

SSVC

Exploitation: none Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-07-24 15:03 UTC

CWE

CWE-369 - dos
CWE-369 - Divide By Zero

Assigner

zephyr mitre root

References

2 references

URL	Tags
https://github.com/zephyrproject-rtos/zephyr/comm…	patch
https://github.com/zephyrproject-rtos/zephyr/secu…

Impacted products

1 product

Vendor	Product	Version
zephyrproject	zephyr	Affected: 3.5.0 , < 4.4.2 (semver)

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-7007",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-07-24T15:03:26.497157Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "problemTypes": [
          {
            "descriptions": [
              {
                "cweId": "CWE-369",
                "description": "CWE-369 Divide By Zero",
                "lang": "en",
                "type": "CWE"
              }
            ]
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-07-24T15:04:01.152Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "collectionURL": "https://github.com/zephyrproject-rtos/zephyr",
          "defaultStatus": "unaffected",
          "packageName": "zephyr",
          "product": "zephyr",
          "programFiles": [
            "subsys/fs/ext2/ext2_impl.c"
          ],
          "vendor": "zephyrproject",
          "versions": [
            {
              "lessThan": "4.4.2",
              "status": "affected",
              "version": "3.5.0",
              "versionType": "semver"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "The Zephyr ext2 file system validates the on-disk superblock in ext2_verify_disk_superblock() (subsys/fs/ext2/ext2_impl.c) before completing a mount. The validator checked the magic number, block size, revision and feature flags, but did not verify that the on-disk fields s_blocks_per_group and s_inodes_per_group are non-zero. Both fields are read directly from the image and are later used as divisors during mount-time initialization.\n\nDuring mount, get_ngroups() divides and modulos s_blocks_count by s_blocks_per_group (reached via ext2_fetch_block_group() from ext2_init_fs()), and get_itable_entry() divides (ino - 1) by s_inodes_per_group when fetching the root inode (both in subsys/fs/ext2/ext2_diskops.c). A superblock with either field set to zero therefore causes an integer division by zero during the mount sequence.\n\nAn attacker who can present a crafted ext2 image to a device that mounts ext2 \u2014 removable media such as an SD card or a USB mass-storage device \u2014 can trigger this. On ARMv7-M / ARMv8-M-mainline Cortex-M targets, divide-by-zero trapping is enabled (SCB_CCR_DIV_0_TRP), so the division raises a UsageFault that Zephyr treats as a fatal error, producing a denial of service. The impact is limited to availability; the malformed value is consumed only as a divisor.\n\nThe fix rejects a zero s_blocks_per_group or s_inodes_per_group in the superblock validator, returning -EINVAL so the mount fails before any block-group or inode I/O occurs."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 4.6,
            "baseSeverity": "MEDIUM",
            "vectorString": "CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
            "version": "3.1"
          },
          "format": "CVSS"
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-369",
              "description": "dos",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-31T23:13:27.634Z",
        "orgId": "e2e69745-5e70-4e92-8431-deb5529a81ad",
        "shortName": "zephyr"
      },
      "references": [
        {
          "name": "Fix commit",
          "tags": [
            "patch"
          ],
          "url": "https://github.com/zephyrproject-rtos/zephyr/commit/babc0900ed40e6c023ccc26aa1a321f9388b66af"
        },
        {
          "name": "GHSA-wrf2-79mm-cvw5",
          "url": "https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-wrf2-79mm-cvw5"
        }
      ],
      "title": "Division by zero in Zephyr ext2 superblock parsing allows DoS via crafted filesystem image",
      "x_generator": {
        "engine": "cvelib 1.8.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "e2e69745-5e70-4e92-8431-deb5529a81ad",
    "assignerShortName": "zephyr",
    "cveId": "CVE-2026-7007",
    "datePublished": "2026-07-24T13:48:24.831Z",
    "dateReserved": "2026-04-24T22:00:52.689Z",
    "dateUpdated": "2026-08-31T23:13:27.634Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

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.
Browse all ATT&CK techniques and the vulnerabilities related to each.

Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.