« Volver al listado

CVE-2026-2266

Estado: AnalizadaAlta (7.4)—

An improper neutralization of input vulnerability was identified in GitHub Enterprise Server that allowed DOM-based cross-site scripting via task list content. The task list content extraction logic did not properly re-encode browser-decoded text nodes before rendering, allowing user-supplied HTML to be injected into the page. An authenticated attacker could craft malicious task list items in issues or pull requests to execute arbitrary scripts in the context of another user's browser session. This vulnerability affected all versions of GitHub Enterprise Server prior to 3.20 and was fixed in versions 3.18.6 and 3.19.3. 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.

DOM-based XSS en GitHub Enterprise Server (CWE-79) permite ejecutar scripts JavaScript en navegador del usuario. Vector CVSS muestra AV:N (red) y UI:P (requiere interacción). Atacante autenticado inyecta HTML malicioso en listas de tareas.

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

Restrict Web-Based ContentUser TrainingExecution PreventionBehavior Prevention on EndpointDisable or Remove Feature or ProgramApplication Isolation and Sandboxing

Tecnologías afectadas (1)

Github — Enterprise Server

CWE

Referencias

JSON original (NVD)

Mostrar
{
  "id": "CVE-2026-2266",
  "cveTags": [],
  "metrics": {
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-2266",
          "role": "CISA Coordinator",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "total"
            }
          ],
          "version": "2.0.3",
          "timestamp": "2026-03-11T14:15:00.532214Z"
        }
      }
    ],
    "cvssMetricV31": [
      {
        "type": "Primary",
        "source": "nvd@nist.gov",
        "cvssData": {
          "scope": "CHANGED",
          "version": "3.1",
          "baseScore": 5.4,
          "attackVector": "NETWORK",
          "baseSeverity": "MEDIUM",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N",
          "integrityImpact": "LOW",
          "userInteraction": "REQUIRED",
          "attackComplexity": "LOW",
          "availabilityImpact": "NONE",
          "privilegesRequired": "LOW",
          "confidentialityImpact": "LOW"
        },
        "impactScore": 2.7,
        "exploitabilityScore": 2.3
      }
    ],
    "cvssMetricV40": [
      {
        "type": "Secondary",
        "source": "product-cna@github.com",
        "cvssData": {
          "Safety": "NOT_DEFINED",
          "version": "4.0",
          "Recovery": "NOT_DEFINED",
          "baseScore": 7.4,
          "Automatable": "NOT_DEFINED",
          "attackVector": "NETWORK",
          "baseSeverity": "HIGH",
          "valueDensity": "NOT_DEFINED",
          "vectorString": "CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:P/VC:H/VI:H/VA:N/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": "PASSIVE",
          "attackComplexity": "LOW",
          "attackRequirements": "PRESENT",
          "privilegesRequired": "LOW",
          "subIntegrityImpact": "NONE",
          "vulnIntegrityImpact": "HIGH",
          "integrityRequirement": "NOT_DEFINED",
          "modifiedAttackVector": "NOT_DEFINED",
          "subAvailabilityImpact": "NONE",
          "vulnAvailabilityImpact": "NONE",
          "availabilityRequirement": "NOT_DEFINED",
          "modifiedUserInteraction": "NOT_DEFINED",
          "modifiedAttackComplexity": "NOT_DEFINED",
          "subConfidentialityImpact": "NONE",
          "vulnConfidentialityImpact": "HIGH",
          "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": "3.18.6",
                  "status": "unaffected"
                }
              ],
              "version": "3.18.0",
              "versionType": "semver",
              "lessThanOrEqual": "3.18.5"
            },
            {
              "status": "affected",
              "changes": [
                {
                  "at": "3.19.3",
                  "status": "unaffected"
                }
              ],
              "version": "3.19.0",
              "versionType": "semver",
              "lessThanOrEqual": "3.19.2"
            }
          ],
          "defaultStatus": "unaffected"
        }
      ]
    }
  ],
  "published": "2026-03-10T20:16:39.610",
  "references": [
    {
      "url": "https://docs.github.com/en/enterprise-server@3.18/admin/release-notes#3.18.6",
      "tags": [
        "Release Notes"
      ],
      "source": "product-cna@github.com"
    },
    {
      "url": "https://docs.github.com/en/enterprise-server@3.19/admin/release-notes#3.19.3",
      "tags": [
        "Release Notes"
      ],
      "source": "product-cna@github.com"
    }
  ],
  "vulnStatus": "Analyzed",
  "weaknesses": [
    {
      "type": "Secondary",
      "source": "product-cna@github.com",
      "description": [
        {
          "lang": "en",
          "value": "CWE-79"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "An improper neutralization of input vulnerability was identified in GitHub Enterprise Server that allowed DOM-based cross-site scripting via task list content. The task list content extraction logic did not properly re-encode browser-decoded text nodes before rendering, allowing user-supplied HTML to be injected into the page. An authenticated attacker could craft malicious task list items in issues or pull requests to execute arbitrary scripts in the context of another user's browser session. This vulnerability affected all versions of GitHub Enterprise Server prior to 3.20 and was fixed in versions 3.18.6 and 3.19.3. This vulnerability was reported via the GitHub Bug Bounty program."
    },
    {
      "lang": "es",
      "value": "Una vulnerabilidad de neutralización de entrada inadecuada fue identificada en GitHub Enterprise Server que permitía cross-site scripting basado en DOM a través del contenido de listas de tareas. La lógica de extracción de contenido de listas de tareas no recodificaba correctamente los nodos de texto decodificados por el navegador antes de la renderización, permitiendo que HTML proporcionado por el usuario fuera inyectado en la página. Un atacante autenticado podría crear elementos maliciosos de listas de tareas en incidencias o solicitudes de extracción para ejecutar scripts arbitrarios en el contexto de la sesión del navegador de otro usuario. Esta vulnerabilidad afectó a todas las versiones de GitHub Enterprise Server anteriores a la 3.20 y fue corregida en las versiones 3.18.6 y 3.19.3. Esta vulnerabilidad fue reportada a través del programa GitHub Bug Bounty."
    }
  ],
  "lastModified": "2026-06-17T10:30:40.617",
  "configurations": [
    {
      "nodes": [
        {
          "negate": false,
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:a:github:enterprise_server:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "8BFED257-8777-4417-9ADF-3B6169F998CE",
              "versionEndExcluding": "3.18.6"
            },
            {
              "criteria": "cpe:2.3:a:github:enterprise_server:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "F7BDDDA3-FE7D-45F6-842C-0D023D926E18",
              "versionEndExcluding": "3.19.3",
              "versionStartIncluding": "3.19.0"
            }
          ],
          "operator": "OR"
        }
      ]
    }
  ],
  "sourceIdentifier": "product-cna@github.com"
}