CVE-2026-42171

{
  "id": "CVE-2026-42171",
  "sourceIdentifier": "[email protected]",
  "published": "2026-04-24T22:16:01.540",
  "lastModified": "2026-10-26T21:10:00.170",
  "vulnStatus": "Analyzed",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "NSIS (Nullsoft Scriptable Install System) 3.06.1 before 3.12 sometimes uses the Low IL temp directory when executing as SYSTEM, allowing local attackers to gain privileges (if they can cause my_GetTempFileName to return 0, as shown in the references)."
    },
    {
      "lang": "es",
      "value": "NSIS (Nullsoft Scriptable Install System) 3.06.1 anterior a 3.12 a veces utiliza el directorio temporal de IL bajo cuando se ejecuta como SYSTEM, permitiendo a atacantes locales obtener privilegios (si pueden hacer que my_GetTempFileName devuelva 0, como se muestra en las referencias)."
    }
  ],
  "affected": [
    {
      "source": "[email protected]",
      "affectedData": [
        {
          "vendor": "Nullsoft",
          "product": "Nullsoft Scriptable Install System",
          "defaultStatus": "unaffected",
          "versions": [
            {
              "version": "3.06.1",
              "lessThan": "3.12",
              "versionType": "custom",
              "status": "affected"
            }
          ]
        }
      ]
    }
  ],
  "metrics": {
    "cvssMetricV31": [
      {
        "source": "[email protected]",
        "type": "Secondary",
        "cvssData": {
          "version": "3.1",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H",
          "baseScore": 7.8,
          "baseSeverity": "HIGH",
          "attackVector": "LOCAL",
          "attackComplexity": "LOW",
          "privilegesRequired": "NONE",
          "userInteraction": "REQUIRED",
          "scope": "UNCHANGED",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "availabilityImpact": "HIGH"
        },
        "exploitabilityScore": 1.8,
        "impactScore": 5.9
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "timestamp": "2026-04-25T01:56:27.818440Z",
          "id": "CVE-2026-42171",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "total"
            }
          ],
          "role": "CISA Coordinator",
          "version": "2.0.3"
        }
      }
    ]
  },
  "weaknesses": [
    {
      "source": "[email protected]",
      "type": "Secondary",
      "description": [
        {
          "lang": "en",
          "value": "CWE-427"
        }
      ]
    }
  ],
  "configurations": [
    {
      "nodes": [
        {
          "operator": "OR",
          "negate": false,
          "cpeMatch": [
            {
              "vulnerable": true,
              "criteria": "cpe:2.3:a:nullsoft:nullsoft_scriptable_install_system:*:*:*:*:*:*:*:*",
              "versionStartIncluding": "3.06.1",
              "versionEndExcluding": "3.12",
              "matchCriteriaId": "7A2CA663-6F00-478D-BAFC-D53DB9A06C25"
            }
          ]
        }
      ]
    }
  ],
  "references": [
    {
      "url": "https://github.com/NSIS-Dev/nsis/blob/7359413009afd4f0fff472d841fc2f2cc0e0a5f8/Source/exehead/util.c#L475-L484",
      "source": "[email protected]",
      "tags": [
        "Product"
      ]
    },
    {
      "url": "https://github.com/NSIS-Dev/nsis/commit/8e6f02205d5f22da6c7855dbfe59b2af667330ca",
      "source": "[email protected]",
      "tags": [
        "Patch"
      ]
    },
    {
      "url": "https://learn.microsoft.com/en-us/windows/win32/api/winbase/nf-winbase-gettempfilename",
      "source": "[email protected]",
      "tags": [
        "Product"
      ]
    },
    {
      "url": "https://nsis.sourceforge.io/Docs/AppendixF.html#v3.12-cl",
      "source": "[email protected]",
      "tags": [
        "Release Notes"
      ]
    }
  ]
}