{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "source": "REFERENCES"
          },
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "8e6f02205d5f22da6c7855dbfe59b2af667330ca"
            }
          ],
          "repo": "https://github.com/nsis-dev/nsis",
          "type": "GIT"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "mitre",
    "cwe_ids": [
      "CWE-427"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/42xxx/CVE-2026-42171.json",
    "unresolved_ranges": [
      {
        "extracted_events": [
          {
            "introduced": "3.06.1"
          },
          {
            "fixed": "3.12"
          }
        ],
        "source": "AFFECTED_FIELD"
      },
      {
        "extracted_events": [
          {
            "introduced": "3.06.1"
          },
          {
            "fixed": "3.12"
          }
        ],
        "source": "CPE_FIELD"
      },
      {
        "extracted_events": [
          {
            "introduced": "3.06.1"
          },
          {
            "fixed": "3.12"
          }
        ],
        "source": "DESCRIPTION"
      }
    ]
  },
  "details": "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).",
  "id": "CVE-2026-42171",
  "modified": "2026-08-12T03:51:10.817264132Z",
  "published": "2026-04-24T21:20:35.525Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/NSIS-Dev/nsis/blob/7359413009afd4f0fff472d841fc2f2cc0e0a5f8/Source/exehead/util.c#L475-L484"
    },
    {
      "type": "WEB",
      "url": "https://learn.microsoft.com/en-us/windows/win32/api/winbase/nf-winbase-gettempfilename"
    },
    {
      "type": "WEB",
      "url": "https://nsis.sourceforge.io/Docs/AppendixF.html#v3.12-cl"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/42xxx/CVE-2026-42171.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-42171"
    },
    {
      "type": "FIX",
      "url": "https://github.com/NSIS-Dev/nsis/commit/8e6f02205d5f22da6c7855dbfe59b2af667330ca"
    }
  ],
  "schema_version": "1.9.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}