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CVE-2026-39822

Estado: AnalizadaAlta (7.8)—

On Unix systems, opening a file in an os.Root improperly follows symlinks to locations outside of the Root when the final path component of the a path is a symbolic link and the path ends in /. For example, 'root.Open("symlink/")' will open "symlink" even when "symlink" is a symbolic link pointing outside of the root.

CVSS

Probabilidad de explotación (EPSS)

EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).

🎯 Técnicas ATT&CK

Cómo se explota esta vulnerabilidad y qué consigue el atacante, en el lenguaje de MITRE ATT&CK.

AV:L + PR:L sin UI permite escalada local. Symlink traversal fuera de root permite lectura y modificación de archivos sensibles del sistema con permisos elevados.

Inferido por nuestro agente de análisis a partir de la descripción oficial, el vector CVSS y la CWE, y comprobado por un supervisor. Puede contener errores.

🛡️ Mitigaciones ATT&CK que cubren estas técnicas

Threat Intelligence ProgramRestrict File and Directory PermissionsRemote Data StorageExecution PreventionEncrypt Sensitive InformationApplication Isolation and Sandboxing

Tecnologías afectadas (1)

Golang — GO

CWE

Referencias

JSON original (NVD)

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{
  "id": "CVE-2026-39822",
  "cveTags": [],
  "metrics": {
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-39822",
          "role": "CISA Coordinator",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "total"
            }
          ],
          "version": "2.0.3",
          "timestamp": "2026-07-08T18:06:16.360721Z"
        }
      }
    ],
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 7.8,
          "attackVector": "LOCAL",
          "baseSeverity": "HIGH",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
          "integrityImpact": "HIGH",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "confidentialityImpact": "HIGH"
        },
        "impactScore": 5.9,
        "exploitabilityScore": 1.8
      }
    ]
  },
  "affected": [
    {
      "source": "security@golang.org",
      "affectedData": [
        {
          "vendor": "Go standard library",
          "product": "os",
          "versions": [
            {
              "status": "affected",
              "version": "0",
              "lessThan": "1.25.12",
              "versionType": "semver"
            },
            {
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              "version": "1.26.0-0",
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              "versionType": "semver"
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          "collectionURL": "https://pkg.go.dev",
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              "name": "rootOpenFileNolog"
            },
            {
              "name": "openRootInRoot"
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            {
              "name": "OpenInRoot"
            },
            {
              "name": "Root.Create"
            },
            {
              "name": "Root.Open"
            },
            {
              "name": "Root.OpenFile"
            },
            {
              "name": "Root.OpenRoot"
            },
            {
              "name": "Root.ReadFile"
            },
            {
              "name": "Root.WriteFile"
            },
            {
              "name": "rootFS.Open"
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            {
              "name": "rootFS.ReadDir"
            },
            {
              "name": "rootFS.ReadFile"
            }
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  ],
  "published": "2026-07-08T17:17:21.310",
  "references": [
    {
      "url": "https://go.dev/cl/797880",
      "tags": [
        "Patch"
      ],
      "source": "security@golang.org"
    },
    {
      "url": "https://go.dev/issue/79005",
      "tags": [
        "Issue Tracking",
        "Patch"
      ],
      "source": "security@golang.org"
    },
    {
      "url": "https://groups.google.com/g/golang-announce/c/OrmQE_Yp5Sc",
      "tags": [
        "Mailing List",
        "Patch",
        "Vendor Advisory"
      ],
      "source": "security@golang.org"
    },
    {
      "url": "https://pkg.go.dev/vuln/GO-2026-4970",
      "tags": [
        "Vendor Advisory"
      ],
      "source": "security@golang.org"
    }
  ],
  "vulnStatus": "Analyzed",
  "weaknesses": [
    {
      "type": "Secondary",
      "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
      "description": [
        {
          "lang": "en",
          "value": "CWE-61"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "On Unix systems, opening a file in an os.Root improperly follows symlinks to locations outside of the Root when the final path component of the a path is a symbolic link and the path ends in /. For example, 'root.Open(\"symlink/\")' will open \"symlink\" even when \"symlink\" is a symbolic link pointing outside of the root."
    }
  ],
  "lastModified": "2026-09-17T17:10:20.047",
  "configurations": [
    {
      "nodes": [
        {
          "negate": false,
          "cpeMatch": [
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              "versionEndExcluding": "1.26.5",
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}