CVE-2026-9595
Publication date 15 June 2026
Last updated 25 June 2026
Ubuntu priority
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.
Status
| Package | Ubuntu Release | Status |
|---|---|---|
| node-webpack | 26.04 LTS resolute |
Needs evaluation
|
| 25.10 questing |
Needs evaluation
|
|
| 24.04 LTS noble |
Needs evaluation
|
|
| 22.04 LTS jammy |
Needs evaluation
|
|
| 20.04 LTS focal |
Needs evaluation
|
|
| 18.04 LTS bionic |
Needs evaluation
|
|
| vue.js | 26.04 LTS resolute |
Needs evaluation
|
| 25.10 questing |
Needs evaluation
|
|
| 24.04 LTS noble |
Needs evaluation
|
|
| 22.04 LTS jammy |
Needs evaluation
|
|
| 20.04 LTS focal |
Needs evaluation
|
Severity score breakdown
CVSS version: CVSS v3.0
Base score
5.3 · Medium
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
References
Other references
- https://www.cve.org/CVERecord?id=CVE-2026-9595
- 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