« Volver al listado

CVE-2026-17556

Estado: AnalizadaAlta (8.8)—

A path traversal vulnerability was identified in GitHub Enterprise Server that allowed an unauthenticated attacker to delete arbitrary files and directories on the instance, including the entire user storage directory containing Git LFS objects, release assets, attachments, and avatars. The X-GitHub-Request-Id request header was used without sanitization as a filesystem path segment for the upload buffer directory, so a traversal value pointed the buffer at an arbitrary path and the deferred cleanup routine recursively removed the traversed target.

Leer descripción completaMostrar menos

Exploitation required only network reachability to the instance and no authentication, and it worked even when private mode was enabled. This vulnerability affected all versions of GitHub Enterprise Server prior to 3.22 and was fixed in versions 3.21.4, 3.20.6, 3.19.10, 3.18.13 and 3.17.19. This vulnerability was reported via the GitHub Bug Bounty program.

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.

Path traversal en aplicación web expuesta (T1190, AV:N/PR:N/UI:N). Impactos: eliminación de archivos arbitrarios (T1565.002 - Transmitted Data Manipulation) y destrucción de datos críticos (avatares, assets, LFS). No es lectura (T1005) sino eliminación destructiva.

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

Vulnerability ScanningPrivileged Account ManagementNetwork SegmentationLimit Access to Resource Over NetworkFilter Network TrafficEncrypt Sensitive Information

Tecnologías afectadas (1)

Github — Enterprise Server

CWE

Referencias

JSON original (NVD)

Mostrar
{
  "id": "CVE-2026-17556",
  "cveTags": [],
  "metrics": {
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-17556",
          "role": "CISA Coordinator",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "yes"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "version": "2.0.3",
          "timestamp": "2026-08-06T13:10:54.530503Z"
        }
      }
    ],
    "cvssMetricV31": [
      {
        "type": "Primary",
        "source": "nvd@nist.gov",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 9.1,
          "attackVector": "NETWORK",
          "baseSeverity": "CRITICAL",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H",
          "integrityImpact": "HIGH",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "confidentialityImpact": "NONE"
        },
        "impactScore": 5.2,
        "exploitabilityScore": 3.9
      }
    ],
    "cvssMetricV40": [
      {
        "type": "Secondary",
        "source": "product-cna@github.com",
        "cvssData": {
          "Safety": "NOT_DEFINED",
          "version": "4.0",
          "Recovery": "NOT_DEFINED",
          "baseScore": 8.8,
          "Automatable": "NOT_DEFINED",
          "attackVector": "NETWORK",
          "baseSeverity": "HIGH",
          "valueDensity": "NOT_DEFINED",
          "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/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",
          "exploitMaturity": "NOT_DEFINED",
          "providerUrgency": "NOT_DEFINED",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "attackRequirements": "NONE",
          "privilegesRequired": "NONE",
          "subIntegrityImpact": "NONE",
          "vulnIntegrityImpact": "HIGH",
          "integrityRequirement": "NOT_DEFINED",
          "modifiedAttackVector": "NOT_DEFINED",
          "subAvailabilityImpact": "NONE",
          "vulnAvailabilityImpact": "HIGH",
          "availabilityRequirement": "NOT_DEFINED",
          "modifiedUserInteraction": "NOT_DEFINED",
          "modifiedAttackComplexity": "NOT_DEFINED",
          "subConfidentialityImpact": "NONE",
          "vulnConfidentialityImpact": "NONE",
          "confidentialityRequirement": "NOT_DEFINED",
          "modifiedAttackRequirements": "NOT_DEFINED",
          "modifiedPrivilegesRequired": "NOT_DEFINED",
          "modifiedSubIntegrityImpact": "NOT_DEFINED",
          "modifiedVulnIntegrityImpact": "NOT_DEFINED",
          "vulnerabilityResponseEffort": "NOT_DEFINED",
          "modifiedSubAvailabilityImpact": "NOT_DEFINED",
          "modifiedVulnAvailabilityImpact": "NOT_DEFINED",
          "modifiedSubConfidentialityImpact": "NOT_DEFINED",
          "modifiedVulnConfidentialityImpact": "NOT_DEFINED"
        }
      }
    ]
  },
  "affected": [
    {
      "source": "product-cna@github.com",
      "affectedData": [
        {
          "vendor": "GitHub",
          "product": "Enterprise Server",
          "versions": [
            {
              "status": "affected",
              "changes": [
                {
                  "at": "3.17.19",
                  "status": "unaffected"
                }
              ],
              "version": "3.17.0",
              "versionType": "semver",
              "lessThanOrEqual": "3.17.18"
            },
            {
              "status": "affected",
              "changes": [
                {
                  "at": "3.18.13",
                  "status": "unaffected"
                }
              ],
              "version": "3.18.0",
              "versionType": "semver",
              "lessThanOrEqual": "3.18.12"
            },
            {
              "status": "affected",
              "changes": [
                {
                  "at": "3.19.10",
                  "status": "unaffected"
                }
              ],
              "version": "3.19.0",
              "versionType": "semver",
              "lessThanOrEqual": "3.19.9"
            },
            {
              "status": "affected",
              "changes": [
                {
                  "at": "3.20.6",
                  "status": "unaffected"
                }
              ],
              "version": "3.20.0",
              "versionType": "semver",
              "lessThanOrEqual": "3.20.5"
            },
            {
              "status": "affected",
              "changes": [
                {
                  "at": "3.21.4",
                  "status": "unaffected"
                }
              ],
              "version": "3.21.0",
              "versionType": "semver",
              "lessThanOrEqual": "3.21.3"
            }
          ],
          "defaultStatus": "affected"
        }
      ]
    }
  ],
  "published": "2026-08-05T20:17:06.047",
  "references": [
    {
      "url": "https://docs.github.com/en/enterprise-server@3.17/admin/release-notes#3.17.19",
      "tags": [
        "Product",
        "Release Notes"
      ],
      "source": "product-cna@github.com"
    },
    {
      "url": "https://docs.github.com/en/enterprise-server@3.18/admin/release-notes#3.18.13",
      "tags": [
        "Product",
        "Release Notes"
      ],
      "source": "product-cna@github.com"
    },
    {
      "url": "https://docs.github.com/en/enterprise-server@3.19/admin/release-notes#3.19.10",
      "tags": [
        "Product",
        "Release Notes"
      ],
      "source": "product-cna@github.com"
    },
    {
      "url": "https://docs.github.com/en/enterprise-server@3.20/admin/release-notes#3.20.6",
      "tags": [
        "Product",
        "Release Notes"
      ],
      "source": "product-cna@github.com"
    },
    {
      "url": "https://docs.github.com/en/enterprise-server@3.21/admin/release-notes#3.21.4",
      "tags": [
        "Product",
        "Release Notes"
      ],
      "source": "product-cna@github.com"
    }
  ],
  "vulnStatus": "Analyzed",
  "weaknesses": [
    {
      "type": "Secondary",
      "source": "product-cna@github.com",
      "description": [
        {
          "lang": "en",
          "value": "CWE-22"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "A path traversal vulnerability was identified in GitHub Enterprise Server that allowed an unauthenticated attacker to delete arbitrary files and directories on the instance, including the entire user storage directory containing Git LFS objects, release assets, attachments, and avatars. The X-GitHub-Request-Id request header was used without sanitization as a filesystem path segment for the upload buffer directory, so a traversal value pointed the buffer at an arbitrary path and the deferred cleanup routine recursively removed the traversed target. Exploitation required only network reachability to the instance and no authentication, and it worked even when private mode was enabled. This vulnerability affected all versions of GitHub Enterprise Server prior to 3.22 and was fixed in versions 3.21.4, 3.20.6, 3.19.10, 3.18.13 and 3.17.19. This vulnerability was reported via the GitHub Bug Bounty program."
    }
  ],
  "lastModified": "2026-08-18T18:08:03.440",
  "configurations": [
    {
      "nodes": [
        {
          "negate": false,
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:a:github:enterprise_server:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "384AEDA5-C4FB-4C1E-A158-C5824DC8C7E9",
              "versionEndExcluding": "3.17.19"
            },
            {
              "criteria": "cpe:2.3:a:github:enterprise_server:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "209CD8A4-0690-4FBE-8FBF-D8DC01B4C5BA",
              "versionEndExcluding": "3.18.13",
              "versionStartIncluding": "3.18.0"
            },
            {
              "criteria": "cpe:2.3:a:github:enterprise_server:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "E67B7806-5FA2-4E22-AC7E-5747D56AC167",
              "versionEndExcluding": "3.19.10",
              "versionStartIncluding": "3.19.0"
            },
            {
              "criteria": "cpe:2.3:a:github:enterprise_server:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "86002896-8D6A-42EA-930C-D8E7C5DA3D70",
              "versionEndExcluding": "3.20.6",
              "versionStartIncluding": "3.20.0"
            },
            {
              "criteria": "cpe:2.3:a:github:enterprise_server:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "54A93841-1037-4139-A61E-E23BDAB5DD8A",
              "versionEndExcluding": "3.21.4",
              "versionStartIncluding": "3.21.0"
            }
          ],
          "operator": "OR"
        }
      ]
    }
  ],
  "sourceIdentifier": "product-cna@github.com"
}