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CVE-2026-41091

Estado: AnalizadaAlta (7.8)⚠ Explotación activa

Improper link resolution before file access ('link following') in Microsoft Defender allows an authorized attacker to elevate privileges locally.

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).

CISA KEV — explotada activamente

🎯 Técnicas ATT&CK

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

CWE-59 (link following) con AV:L/PR:L permite escalada local de privilegios. Vector sin ejecución remota pero impacto de C:H/I:H/A:H. Ransomware frecuente indica T1548 (abuso de mecanismos de elevación).

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

Execution PreventionUpdate SoftwareUser Account ManagementThreat Intelligence ProgramRestrict File and Directory PermissionsPrivileged Account Management

Tecnologías afectadas (1)

Microsoft — Malware Protection Engine

CWE

Referencias

JSON original (NVD)

Mostrar
{
  "id": "CVE-2026-41091",
  "cveTags": [],
  "metrics": {
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-41091",
          "role": "CISA Coordinator",
          "options": [
            {
              "exploitation": "active"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "total"
            }
          ],
          "version": "2.0.3",
          "timestamp": "2026-05-20T00:00:00+00:00"
        }
      }
    ],
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "secure@microsoft.com",
        "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": "secure@microsoft.com",
      "affectedData": [
        {
          "vendor": "Microsoft",
          "product": "Microsoft Malware Protection Engine",
          "versions": [
            {
              "status": "affected",
              "version": "1.1.0.0",
              "lessThan": "1.1.26040.8",
              "versionType": "custom"
            }
          ]
        }
      ]
    }
  ],
  "published": "2026-05-20T13:16:29.173",
  "references": [
    {
      "url": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-41091",
      "tags": [
        "Vendor Advisory"
      ],
      "source": "secure@microsoft.com"
    },
    {
      "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-41091",
      "tags": [
        "Third Party Advisory",
        "US Government Resource"
      ],
      "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0"
    }
  ],
  "vulnStatus": "Analyzed",
  "weaknesses": [
    {
      "type": "Secondary",
      "source": "secure@microsoft.com",
      "description": [
        {
          "lang": "en",
          "value": "CWE-59"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "Improper link resolution before file access ('link following') in Microsoft Defender allows an authorized attacker to elevate privileges locally."
    },
    {
      "lang": "es",
      "value": "Resolución de enlaces incorrecta antes del acceso a archivos ('seguimiento de enlaces') en Microsoft Defender permite a un atacante autorizado elevar privilegios localmente."
    }
  ],
  "lastModified": "2026-07-24T10:10:00.197",
  "cisaActionDue": "2026-06-03",
  "cisaExploitAdd": "2026-05-20",
  "configurations": [
    {
      "nodes": [
        {
          "negate": false,
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:a:microsoft:malware_protection_engine:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "AD1882FA-1447-46F7-A592-142F55820A60",
              "versionEndExcluding": "1.1.26040.8",
              "versionStartIncluding": "1.1.26030.3008"
            }
          ],
          "operator": "OR"
        }
      ]
    }
  ],
  "sourceIdentifier": "secure@microsoft.com",
  "cisaRequiredAction": "Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.",
  "cisaVulnerabilityName": "Microsoft Defender Link Following Vulnerability"
}