vite allows server.fs.deny bypass via backslash on Windows

CISA KEV is observed exploitation evidence. FIRST EPSS is a dated prediction of exploitation in the next 30 days. Missing scores are unknown. This collector requests predictions only for explicit CVE aliases in the public NuGet archive; Microsoft release views retain their existing prediction scope.

No collected risk observation for these identifiers. This does not establish absence of exploitation or a zero probability.

Vite is a frontend tooling framework for JavaScript. In versions from 2.9.18 to before 3.0.0, 3.2.9 to before 4.0.0, 4.5.3 to before 5.0.0, 5.2.6 to before 5.4.21, 6.0.0 to before 6.4.1, 7.0.0 to before 7.0.8, and 7.1.0 to before 7.1.11, files denied by server.fs.deny were sent if the URL ended with \ when the dev server is running on Windows. Only apps explicitly exposing the Vite dev server to the network and running the dev server on Windows were affected. This issue has been patched in versions 5.4.21, 6.4.1, 7.0.8, and 7.1.11.

Source published

20 Oct 2025 19:57:13 UTC

Source modified

20 Oct 2025 20:17:08 UTC

Observed here

23 Oct 2026 15:48:27 UTC

Source terms

CVE Program Terms of Use

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: cve-program · CVE Program Terms of Use. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 4.0 · 6.0 CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N

Vite is a frontend tooling framework for JavaScript. In versions from 2.9.18 to before 3.0.0, 3.2.9 to before 4.0.0, 4.5.3 to before 5.0.0, 5.2.6 to before 5.4.21, 6.0.0 to before 6.4.1, 7.0.0 to before 7.0.8, and 7.1.0 to before 7.1.11, files denied by server.fs.deny were sent if the URL ended with \ when the dev server is running on Windows. Only apps explicitly exposing the Vite dev server to the network and running the dev server on Windows were affected. This issue has been patched in versions 5.4.21, 6.4.1, 7.0.8, and 7.1.11.

Source published

Oct 20, 2025, 7:57:13 PM (timezone not stated)

Source modified

Oct 20, 2025, 8:17:08 PM (timezone not stated)

Observed here

9 Nov 2026 04:05:56 UTC

Source terms

ENISA EUVD · source terms and attribution apply

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: euvd · ENISA EUVD · source terms and attribution apply. Source text is retained; field grouping and change labels are provided by ChangeIntel.

EUVD CVSS 4.0 · 6.0 CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N

Vite is a frontend tooling framework for JavaScript. In versions from 2.9.18 to before 3.0.0, 3.2.9 to before 4.0.0, 4.5.3 to before 5.0.0, 5.2.6 to before 5.4.21, 6.0.0 to before 6.4.1, 7.0.0 to before 7.0.8, and 7.1.0 to before 7.1.11, files denied by server.fs.deny were sent if the URL ended with \ when the dev server is running on Windows. Only apps explicitly exposing the Vite dev server to the network and running the dev server on Windows were affected. This issue has been patched in versions 5.4.21, 6.4.1, 7.0.8, and 7.1.11.

Source published

20 Oct 2025 20:15:37 UTC

Source modified

8 Oct 2026 22:10:00 UTC

Observed here

25 Oct 2026 03:17:29 UTC

Source terms

NIST NVD usage terms; underlying source attribution retained

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: nvd · NIST NVD usage terms; underlying source attribution retained. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 4.0 · [email protected] · Secondary · 6.0 CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

### Summary Files denied by [`server.fs.deny`](https://vitejs.dev/config/server-options.html#server-fs-deny) were sent if the URL ended with `\` when the dev server is running on Windows. ### Impact Only apps that match the following conditions are affected: - 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)) - running the dev server on Windows ### Details `server.fs.deny` can contain patterns matching against files (by default it includes `.env`, `.env.*`, `*.{crt,pem}` as such patterns). These patterns were able to bypass by using a back slash(`\`). The root cause is that `fs.readFile('/foo.png/')` loads `/foo.png`. ### PoC ```shell npm create vite@latest cd vite-project/ cat "secret" > .env npm install npm run dev curl --request-target /.env\ http://localhost:5173 ``` <img width="1593" height="616" alt="image" src="https://github.com/user-attachments/assets/36212f4e-1d3c-4686-b16f-16b35ca9e175" />

Source published

20 Oct 2025 19:54:28 UTC

Source modified

10 Sep 2026 03:50:29 UTC

Observed here

24 Oct 2026 13:17:17 UTC

Source terms

GitHub Advisory Database · CC-BY-4.0

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · GitHub Advisory Database · CC-BY-4.0. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS_V4 · CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N

Publisher rating · MODERATE