CVE-2026-53571: vite `server.fs.deny` Bypass On Windows Alternate Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-fx2h-pf6j-xcff",
  "modified" : "2026-07-15T22:05:52Z",
  "published" : "2026-06-15T17:17:45Z",
  "aliases" : [ "CVE-2026-53571" ],
  "summary" : "vite: `server.fs.deny` bypass on Windows alternate paths",
  "details" : "### Summary\n\nThe contents of files that are specified by [`server.fs.deny`](https://vite.dev/config/server-options#server-fs-deny) can be returned to the browser on Windows.\n\n### Impact\n\nOnly apps that match the following conditions are affected:\n\n- explicitly exposes the Vite dev server to the network (using `--host` or [`server.host` config option](https://vitejs.dev/config/server-options.html#server-host))\n- the sensitive file exists in the allowed directories specified by [`server.fs.allow`](https://vite.dev/config/server-options#server-fs-allow)\n- either of:\n  - the sensitive file exists in an NTFS volume\n  - the dev server is running on Windows and the sensitive file exists in a volume that 8.3 short name generation is enabled (it is enabled by default on system volumes)\n\n### Details\n\nVite’s dev server denies direct access to sensitive files through `server.fs.deny`, including entries such as `.env`, `.env.*`, and `*.{crt,pem}`. However, on Windows, the deny logic does not correctly normalize NTFS ADS path forms before access checks are applied.\nBecause of this, requests such as `/.env::$DATA?raw` are treated as allowed paths, while Windows resolves them to the original file's default data stream.\n\nSimilar to that, Windows allows accessing a file using a different name with the 8.3 short name compatibility feature. Vite did not reject accessing files via them.\n\n### PoC\n```bash\n$ npm create vite@latest\n$ cd vite-project/\n$ npm install\n$ npm run dev\n```\nAccess via browser at `http://localhost:5173/.env::$DATA?raw`\n<img width=\"388\" height=\"129\" alt=\"deecc1315123883cfd0f9c26a002845a\" src=\"https://github.com/user-attachments/assets/895c6012-4e2e-4a35-babb-69bbf3ee7170\" />\n\nExample expected result:\n- `/.env::$DATA?raw` returns the contents of `.env`\n- `/tls.pem::$DATA?raw` returns the contents of `tls.pem`",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N"
  }, {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "npm",
      "name" : "vite"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "8.0.0"
      }, {
        "fixed" : "8.0.16"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 8.0.15"
    }
  }, {
    "package" : {
      "ecosystem" : "npm",
      "name" : "vite"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "7.0.0"
      }, {
        "fixed" : "7.3.5"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 7.3.4"
    }
  }, {
    "package" : {
      "ecosystem" : "npm",
      "name" : "vite"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "6.4.3"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 6.4.2"
    }
  }, {
    "package" : {
      "ecosystem" : "npm",
      "name" : "vite-plus"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "0.1.24"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 0.1.23"
    }
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/vitejs/vite/security/advisories/GHSA-fx2h-pf6j-xcff"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-53571"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/vitejs/vite"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-200", "CWE-22" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-06-15T17:17:45Z",
    "nvd_published_at" : "2026-06-22T18:16:44Z"
  }
}