FKIE_CVE-2026-68768

Vulnerability from fkie_nvd - Published: 2026-08-22 15:16 - Updated: 2026-10-14 13:10
Severity
6.1 (Medium) - CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:H
Summary
hashcat contains a heap-based buffer overflow (out-of-bounds write) in the outfile_write() function in src/outfile.c. When assembling output into a fixed-size buffer (HCBUFSIZ_LARGE, ~16 MB), the function sequentially appends the username, separator, hash, and plaintext via memcpy without validating that the accumulated length stays within the buffer capacity. When run with --username --show against a crafted hash file containing an oversized username that nearly fills the buffer, the total assembled output exceeds the buffer, causing a heap buffer overflow that can corrupt memory and crash the process.
References
disclosure@vulncheck.comhttps://github.com/hashcat/hashcat
disclosure@vulncheck.comhttps://github.com/hashcat/hashcat/blob/v7.1.2/src/outfile.c#L654-L668
disclosure@vulncheck.comhttps://github.com/hashcat/hashcat/commit/68f56a2d8712867a8520bf4dcf07f6145c23df89
disclosure@vulncheck.comhttps://github.com/hashcat/hashcat/issues/4740
disclosure@vulncheck.comhttps://www.vulncheck.com/advisories/hashcat-through-heap-buffer-overflow-in-outfile-write-via-oversized-username
134c704f-9b21-4f2e-91b3-4a467353bcc0https://github.com/hashcat/hashcat/issues/4740
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "hashcat",
          "vendor": "hashcat",
          "versions": [
            {
              "lessThanOrEqual": "7.1.2",
              "status": "affected",
              "version": "0",
              "versionType": "semver"
            }
          ]
        }
      ],
      "source": "disclosure@vulncheck.com"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "hashcat contains a heap-based buffer overflow (out-of-bounds write) in the outfile_write() function in src/outfile.c. When assembling output into a fixed-size buffer (HCBUFSIZ_LARGE, ~16 MB), the function sequentially appends the username, separator, hash, and plaintext via memcpy without validating that the accumulated length stays within the buffer capacity. When run with --username --show against a crafted hash file containing an oversized username that nearly fills the buffer, the total assembled output exceeds the buffer, causing a heap buffer overflow that can corrupt memory and crash the process."
    },
    {
      "lang": "es",
      "value": "hashcat contiene un desbordamiento de b\u00fafer basado en mont\u00edculo (escritura fuera de l\u00edmites) en la funci\u00f3n outfile_write() en src/outfile.c. Al ensamblar la salida en un b\u00fafer de tama\u00f1o fijo (HCBUFSIZ_LARGE, ~16 MB), la funci\u00f3n a\u00f1ade secuencialmente el nombre de usuario, el separador, el hash y el texto plano a trav\u00e9s de memcpy sin validar que la longitud acumulada se mantenga dentro de la capacidad del b\u00fafer. Cuando se ejecuta con --username --show contra un archivo de hash manipulado que contiene un nombre de usuario sobredimensionado que casi llena el b\u00fafer, la salida total ensamblada excede el b\u00fafer, causando un desbordamiento de b\u00fafer basado en mont\u00edculo que puede corromper la memoria y bloquear el proceso."
    }
  ],
  "id": "CVE-2026-68768",
  "lastModified": "2026-10-14T13:10:00.187",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "LOCAL",
          "availabilityImpact": "HIGH",
          "baseScore": 6.1,
          "baseSeverity": "MEDIUM",
          "confidentialityImpact": "NONE",
          "integrityImpact": "LOW",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "REQUIRED",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 1.8,
        "impactScore": 4.2,
        "source": "disclosure@vulncheck.com",
        "type": "Secondary"
      }
    ],
    "cvssMetricV40": [
      {
        "cvssData": {
          "Automatable": "NOT_DEFINED",
          "Recovery": "NOT_DEFINED",
          "Safety": "NOT_DEFINED",
          "attackComplexity": "LOW",
          "attackRequirements": "NONE",
          "attackVector": "LOCAL",
          "availabilityRequirement": "NOT_DEFINED",
          "baseScore": 6.9,
          "baseSeverity": "MEDIUM",
          "confidentialityRequirement": "NOT_DEFINED",
          "exploitMaturity": "NOT_DEFINED",
          "integrityRequirement": "NOT_DEFINED",
          "modifiedAttackComplexity": "NOT_DEFINED",
          "modifiedAttackRequirements": "NOT_DEFINED",
          "modifiedAttackVector": "NOT_DEFINED",
          "modifiedPrivilegesRequired": "NOT_DEFINED",
          "modifiedSubAvailabilityImpact": "NOT_DEFINED",
          "modifiedSubConfidentialityImpact": "NOT_DEFINED",
          "modifiedSubIntegrityImpact": "NOT_DEFINED",
          "modifiedUserInteraction": "NOT_DEFINED",
          "modifiedVulnAvailabilityImpact": "NOT_DEFINED",
          "modifiedVulnConfidentialityImpact": "NOT_DEFINED",
          "modifiedVulnIntegrityImpact": "NOT_DEFINED",
          "privilegesRequired": "NONE",
          "providerUrgency": "NOT_DEFINED",
          "subAvailabilityImpact": "NONE",
          "subConfidentialityImpact": "NONE",
          "subIntegrityImpact": "NONE",
          "userInteraction": "PASSIVE",
          "valueDensity": "NOT_DEFINED",
          "vectorString": "CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:N/VI:L/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
          "version": "4.0",
          "vulnAvailabilityImpact": "HIGH",
          "vulnConfidentialityImpact": "NONE",
          "vulnIntegrityImpact": "LOW",
          "vulnerabilityResponseEffort": "NOT_DEFINED"
        },
        "source": "disclosure@vulncheck.com",
        "type": "Secondary"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-68768",
          "options": [
            {
              "exploitation": "poc"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-08-24T18:31:30.947115Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2026-08-22T15:16:20.903",
  "references": [
    {
      "source": "disclosure@vulncheck.com",
      "url": "https://github.com/hashcat/hashcat"
    },
    {
      "source": "disclosure@vulncheck.com",
      "url": "https://github.com/hashcat/hashcat/blob/v7.1.2/src/outfile.c#L654-L668"
    },
    {
      "source": "disclosure@vulncheck.com",
      "url": "https://github.com/hashcat/hashcat/commit/68f56a2d8712867a8520bf4dcf07f6145c23df89"
    },
    {
      "source": "disclosure@vulncheck.com",
      "url": "https://github.com/hashcat/hashcat/issues/4740"
    },
    {
      "source": "disclosure@vulncheck.com",
      "url": "https://www.vulncheck.com/advisories/hashcat-through-heap-buffer-overflow-in-outfile-write-via-oversized-username"
    },
    {
      "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
      "url": "https://github.com/hashcat/hashcat/issues/4740"
    }
  ],
  "sourceIdentifier": "disclosure@vulncheck.com",
  "vulnStatus": "Deferred",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-120"
        }
      ],
      "source": "disclosure@vulncheck.com",
      "type": "Secondary"
    }
  ]
}



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