Vulnerability-Lookup

GHSA-8VM2-MJFF-2GG2

Vulnerability from github – Published: 2026-07-01 15:35 – Updated: 2026-07-01 15:35

Details

FatFs R0.16 and earlier contains a downstream-caller vulnerability pattern associated with FatFs long filename handling. With LFN enabled, fno.fname can be up to 255 characters; many callers copy it into short fixed buffers without bounds checks, causing overflow. This maps to CWE-120 (Buffer Copy without Checking Size of Input). Estimated CVSS v3.1 vector: CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H (7.6, High). The estimated CISA SSVC vectors are Exploitation: PoC, Technical Impact: Total.

Severity

7.6 (High)


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

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{
  "affected": [],
  "aliases": [
    "CVE-2026-6688"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-120"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-07-01T15:17:13Z",
    "severity": "HIGH"
  },
  "details": "FatFs R0.16 and earlier contains a downstream-caller vulnerability pattern associated with FatFs long filename handling. With LFN enabled, fno.fname can be up to 255 characters; many callers copy it into short fixed buffers without bounds checks, causing overflow. This maps to CWE-120 (Buffer Copy without Checking Size of Input). Estimated CVSS v3.1 vector: CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H (7.6, High). The estimated CISA SSVC vectors are Exploitation: PoC, Technical Impact: Total.",
  "id": "GHSA-8vm2-mjff-2gg2",
  "modified": "2026-07-01T15:35:21Z",
  "published": "2026-07-01T15:35:21Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-6688"
    },
    {
      "type": "WEB",
      "url": "https://elm-chan.org/fsw/ff"
    },
    {
      "type": "WEB",
      "url": "https://github.com/runZeroInc/vulns-2026-fatfs-chance"
    },
    {
      "type": "WEB",
      "url": "https://www.runzero.com/advisories/fatfs-long-fn-of-downstream-cve-2026-6688"
    },
    {
      "type": "WEB",
      "url": "https://www.runzero.com/blog/fatfs-bugs"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}

CVE-2026-6688 (GCVE-0-2026-6688)

Vulnerability from cvelistv5 – Published: 2026-07-01 14:01 – Updated: 2026-07-01 15:06

Title

FatFs Buffer Overflow via Unbounded LFN Filename Copy

Summary

Severity

7.6 (High)


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

SSVC

Exploitation: poc Automatable: no Technical Impact: total

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-07-01 15:06 UTC

CWE

CWE-120 - Buffer Copy without Checking Size of Input

Assigner

runZero icscert root

References

4 references

URL	Tags
https://www.runzero.com/blog/fatfs-bugs/	third-party-advisory
https://github.com/runZeroInc/vulns-2026-fatfs-chance	technical-description
https://elm-chan.org/fsw/ff/	product
https://www.runzero.com/advisories/fatfs-long-fn-…	third-party-advisory

Impacted products

1 product

Vendor	Product	Version
ChaN	FatFs	Affected: 0 , ≤ R0.16 (custom)

Date Public

2026-07-01 13:00

Credits

HD Moore of runZero, Inc. Tod Beardsley of runZero, Inc.

Show details on NVD website

JSON

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  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-6688",
                "options": [
                  {
                    "Exploitation": "poc"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "total"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-07-01T15:06:55.618764Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
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        "providerMetadata": {
          "dateUpdated": "2026-07-01T15:06:59.026Z",
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        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
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          "vendor": "ChaN",
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          "value": "HD Moore of runZero, Inc."
        },
        {
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          "type": "coordinator",
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        }
      ],
      "datePublic": "2026-07-01T13:00:00.000Z",
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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.

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.

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GHSA-8VM2-MJFF-2GG2

CVE-2026-6688 (GCVE-0-2026-6688)

Tags

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