CVE-2026-9595
MEDIUM SEVERITYCVSS Score & Metrics
Base Score
5.3 / 10
Vector String
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Vulnerability Description
Impact: When a user-configured proxy on webpack-dev-server has a broad context (e.g. /) and ws: true, it also intercepts the dev server's own HMR WebSocket and forwards it to the proxy target. This leaks the browser's cookies and Origin header to the backend, bypasses the dev server's Host/Origin validation, and corrupts the HMR socket (both HMR and the proxy end up writing to the same socket).
Patches: Fixed in webpack-dev-server@5.2.5.
Workarounds: Scope user-defined proxy context to specific paths instead of /, or omit ws: true from the proxy entry when WebSocket forwarding is not required.
Patches: Fixed in webpack-dev-server@5.2.5.
Workarounds: Scope user-defined proxy context to specific paths instead of /, or omit ws: true from the proxy entry when WebSocket forwarding is not required.
Vulnerability Details
Published Date
Last Modified
CWE ID
CWE-346
Source
NVD
External References
- https://cna.openjsf.org/security-advisories.html
- https://github.com/facebook/create-react-app/pull/7444
- https://github.com/vuejs/vue-cli/commit/72ba7505aff2a8314e82aa5082379a77504a1fcb
- https://github.com/webpack/webpack-dev-server/pull/4316
- https://github.com/webpack/webpack-dev-server/security/advisories/GHSA-mx8g-39q3-5c79
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