CVE-2026-39363: vitejs vite · Information Exposure
Affects vitejs viteSource CVE Database V5
Not known to be exploited · public detection template (Nuclei) · CVSS 8.2 High · fixed in 8.0.5 : patch vitejs vite soon.
Data as of 30 Oct 2026, 11:52 UTC
- EPSS
- 3.3% chance of exploitation in 30 days – higher than 88% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 8.0.5, 7.3.2, 6.4.2 +1
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:NExploitation evidence
Disclosed: evidence found.
CVE published 7 Apr 2026
Detectable: evidence found.
Weaponized: evidence found.
Public exploit code: GitHub proofs of concept
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), GitHub proofs of concept, the Metasploit, Exploit-DB and nuclei-templates index as of 30 Oct 2026.
What to do
Upgrade vite to 8.0.5, 7.3.2 or 6.4.2; vite-plus to 0.1.16; vitejs/vite to 7.3.2 or 6.4.2.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| vitejsvite | Affected
| Fixed in
|
| vitejsvite | Affected
| Fixed in
|
| vitejsvite | Affected
| Fixed in
|
| vitejsvite-plus | Affected
| Fixed in
|
npmvitejs/vitepkg:npm/vitejs/viteOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
Fixes for this vulnerability are available in Vite versions 6.4.2, 7.3.2, and 8.0.5. Users should upgrade to these or later versions to remediate the issue. The Red Hat advisory notes that no alternative mitigations meet their criteria for ease of use and applicability, so upgrading is the recommended action. There is no indication that the vulnerability is mitigated by configuration changes or other workarounds.
Description
### Summary [`server.fs`](https://vite.dev/config/server-options#server-fs-strict) check was not enforced to the `fetchModule` method that is exposed in Vite dev server's WebSocket. ### 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)) - WebSocket is not disabled by `server.ws: false` Arbitrary files on the server (development machine, CI environment, container, etc.) can be exposed. ### Details If it is possible to connect to the Vite dev server’s WebSocket **without an `Origin` header**, an attacker can invoke `fetchModule` via the custom WebSocket event `vite:invoke` and combine `file://...` with `?raw` (or `?inline`) to retrieve the contents of arbitrary files on the server as a JavaScript string (e.g., `export default "..."`). The access control enforced in the HTTP request path (such as `server.fs.allow`) is not applied to this WebSocket-based execution path. ### PoC 1. Start the dev server on the target Example (used during validation with this repository): ```bash pnpm -C playground/alias exec vite --host 0.0.0.0 --port 5173 ``` 2. Confirm that access is blocked via the HTTP path (example: arbitrary file) ```bash curl -i 'http://localhost:5173/@fs/etc/passwd?raw' ``` Result: `403 Restricted` (outside the allow list) <img width="3898" height="1014" alt="image" src="https://github.com/user-attachments/assets/f6593377-549c-45d7-b562-5c19833438af" /> 3. Confirm that the same file can be retrieved via the WebSocket path By connecting to the HMR WebSocket without an `Origin` header and sending a `vite:invoke` request that calls `fetchModule` with a `file://...` URL and `?raw`, the file contents are returned as a JavaScript module. <img width="1049" height="296" alt="image" src="https://github.com/user-attachments/assets/af969f7b-d34e-4af4-8adb-5e2b83b31972" /> <img width="1382" height="955" alt="image" src="https://github.com/user-attachments/assets/6a230d2e-197a-4c9c-b373-d0129756d5d7" />
References
- github.com/vitejs/vite/security/advisories/GHSA-p9ff-h696-f583 (opens in a new tab)
- access.redhat.com/security/cve/CVE-2026-39363 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2456179 (opens in a new tab)
- security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-39363.json (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:24761 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:24762 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:24866 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:59153 (opens in a new tab)