{"id":"CVE-2026-112947","aliases":["GHSA-vfpm-58rq-9qcg"],"title":"Vite: First 4 bytes of files outside of `server.fs` setting is exposed by `?vite-wasm-instance`","summary":"Vite: First 4 bytes of files outside of `server.fs` setting is exposed by `?vite-wasm-instance`","severity":"medium","cvss":6.3,"cwe":["CWE-22","CWE-200","CWE-209"],"vendor":"vite","product":"vite","ecosystem":"npm","affected":["vite >= 8.3.0, <= 8.3.2","vite >= 8.2.0, <= 8.2.3","vite-plus >= 0.2.8, <= 1.0.0"],"patched":["vite 8.3.3","vite 8.2.4","vite-plus 1.1.0"],"published":"2026-10-21","updated":"2026-10-21","sourceUpdated":"2026-10-21T16:47:16Z","source":"GHSA","sourceUrl":"https://github.com/advisories/GHSA-vfpm-58rq-9qcg","references":[{"url":"https://github.com/vitejs/vite/security/advisories/GHSA-vfpm-58rq-9qcg"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-112947"},{"url":"https://github.com/vitejs/vite/pull/23655"},{"url":"https://github.com/vitejs/vite/commit/b6c6d2fb3f853aab4092dc25f0d6816a96c23dff"},{"url":"https://github.com/vitejs/vite/commit/ba8b7ab43b4afa5d0292ab4b6e3a7b5033cc9c73"},{"url":"https://github.com/advisories/GHSA-vfpm-58rq-9qcg"}],"tags":["ghsa","npm","cve.org"],"cvssVector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N","ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"partial","timestamp":"2026-10-21T14:24:23.584105Z"},"cvssSource":"cna","epss":0.00502,"epssPercentile":0.42763,"ingestedAt":"2026-10-20T16:10:53.330Z","slug":"CVE-2026-112947","body":"## Overview\n\n### Summary\n\nThe first 4 bytes of files outside of `server.fs` setting can be returned to the browser by a request containing `?vite-wasm-instance`.\n\n### Impact\n\n Only apps that match one of the following conditions are affected:\n\n- explicitly expose the Vite dev server to the network using `--host` or the [`server.host`](https://vite.dev/config/server-options#server-host) option\n- there's a file that has a sensitive information in **the first 4 bytes**\n- uses Node.js or Deno to run Vite (if Bun is used, it is not affected)\n\n### Details\nRequests containing the `?vite-wasm-instance` query are handled by the internal Wasm plugin's `load` hook. The hook removes the query and reads the resulting path directly from disk, but the `server.fs` checks were not applied.\n\nAfter reading the file, Vite attempts to parse it as WebAssembly. When that parse fails, Node and deno throws an error that contains the first 4 bytes of the file.\n\n### PoC\n\nCreate a denied file and start an affected Vite dev server:\n\n```bash\necho 'SECRET_KEY=abc123\\n' > .env\nnpm run dev\ncurl 'http://localhost:5173/.env?vite-wasm-instance'\n```\n\nThis will show\n```\nFailed to parse WASM file \"<root>/.env\": WebAssembly.compile(): expected magic word 00 61 73 6d, found 53 45 43 52 @+0\n```\n\n## Affected packages\n\n- `vite >= 8.3.0, <= 8.3.2`\n- `vite >= 8.2.0, <= 8.2.3`\n- `vite-plus >= 0.2.8, <= 1.0.0`\n\n## Remediation\n\nUpgrade to a patched release:\n\n- `vite 8.3.3`\n- `vite 8.2.4`\n- `vite-plus 1.1.0`","depth":"sunlit","depthScore":35,"depthScoreParts":{"impact":34.7,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}