NPM: webpack-dev-server vulnerable to HMR WebSocket interception via permissive user proxies

NPM: webpack-dev-server vulnerable to HMR WebSocket interception via permissive user proxies vulnerability discovered by ? in WordPress Npm webpack-dev-server versions 5.2.5...

@4399ywkf/core (>=5.0.0, <=5.0.32), @all-star/base (>=0.17.0, <=0.18.2) +323 more potentially affected by CVE-2026-9595 via webpack-dev-server (>=5.0.0, <=5.2.4)

webpack-dev-server NPM version =5.0.0, =5.0.0, =0.17.0, =0.17.0, =0.17.0, =8.0.0-next.2, =18.0.0-beta.3, =18.0.0-beta.3, =18.2.6-RC-1, =18.0.0, =18.0.0-next.0, =0.7.7, =1.0.5-beta.4, =1.0.1-beta.1, =0.18.3, =0.0.1, =0.3.2 and more Source cves: CVE-2026-9595 Source advisory: GHSA-MX8G-39Q3-5C79...

EUVD-2026-36729

webpack-dev-server vulnerable to HMR WebSocket interception via permissive user proxies...

Unintended Proxy or Intermediary ('Confused Deputy')

Overview webpack-dev-server is an Uses webpack with a development server that provides live reloading. It should be used for development only. Affected versions of this package are vulnerable to Unintended Proxy or Intermediary 'Confused Deputy' via permissive user proxy configurations that inclu...

@4399ywkf/core (>=5.0.0, <=5.0.32), @all-star/base (>=0.17.0, <=0.18.2) +323 more potentially affected by CVE-2026-9595 via webpack-dev-server (>=5.0.0, <=5.2.4)

webpack-dev-server NPM version =5.0.0, =5.0.0, =0.17.0, =0.17.0, =0.17.0, =8.0.0-next.2, =18.0.0-beta.3, =18.0.0-beta.3, =18.2.6-RC-1, =18.0.0, =18.0.0-next.0, =0.7.7, =1.0.5-beta.4, =1.0.1-beta.1, =0.18.3, =0.0.1, =0.3.2 and more Source cves: CVE-2026-9595 Source advisory:...

Unintended Proxy or Intermediary ('Confused Deputy')

Overview org.webjars.npm:webpack-dev-server is an Uses webpack with a development server that provides live reloading. It should be used for development only. Affected versions of this package are vulnerable to Unintended Proxy or Intermediary 'Confused Deputy' via permissive user proxy...

UBUNTU-CVE-2026-9595

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...

CVE-2026-9595

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...

-react-file-list-components (1.1.1), -tompan-reacttemplate (>=1.0.1, <=1.1.0) +48495 more potentially affected by CVE-2026-9595 via webpack-dev-server (>=1.2.9, <=5.2.4)

webpack-dev-server NPM version =1.2.9, =1.0.1, =0.1.0, =1.0.0, =0.1.0, =0.1.6 - 0beny1s 1.1.6 - 0scarclassa 1.0.1 - 0scarclassb 1.0.1 - 0scarclassc 1.0.1 - 0scarclassd 1.0.1 - 0scarclasse 1.0.1 - 0scarclassf 1.0.1 - 0scarclassg 1.0.1 - 0scarclassh 1.0.1 and more Source cves: CVE-2026-9595 Source...

CVE-2026-9595

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...

CVE-2026-9595 webpack-dev-server vulnerable to HMR WebSocket interception via permissive user proxies

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...

CVE-2026-9595

The CVE affects webpack-dev-server where a user-configured proxy with a broad context (e.g., /) and ws: true intercepts the dev server’s HMR WebSocket, forwarding it to the proxy target. This can leak cookies and Origin headers to the backend, bypass Host/Origin validation, and corrupt the HMR so...

CVE-2026-9595 webpack-dev-server vulnerable to HMR WebSocket interception via permissive user proxies

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...

PT-2026-49244

Name of the Vulnerable Software and Affected Versions webpack-dev-server versions prior to 5.2.5 Description A permissive user-configured proxy with a broad context e.g., '/' and ws: true intercepts the development server's own Hot Module Replacement HMR WebSocket and forwards it to the proxy...

CVE-2026-9595: Origin Validation Error

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...

EUVD-2026-29404

webpack-dev-server vulnerable to cross-origin source code exposure on non-HTTPS origins...

GHSA-79CF-XCQC-C78W webpack-dev-server vulnerable to cross-origin source code exposure on non-HTTPS origins

Impact When webpack-dev-server is running on a non-HTTPS origin the default, cross-origin requests from malicious websites can load the dev server's JavaScript bundles via tags. The fix introduced in v5.2.1 CVE-2025-30359 relied on Sec-Fetch-Mode and Sec-Fetch-Site request headers to block these...

@4399ywkf/core (>=5.0.0, <=5.0.32), @all-star/base (>=0.17.0, <=0.18.2) +320 more potentially affected by CVE-2026-6402 via webpack-dev-server (>=5.0.0, <=5.2.3)

webpack-dev-server NPM version =5.0.0, =5.0.0, =0.17.0, =0.17.0, =0.17.0, =8.0.0-next.2, =18.0.0-beta.3, =18.0.0-beta.3, =18.2.6-RC-1, =18.0.0, =18.0.0-next.0, =1.0.5-beta.4, =1.0.1-beta.1, =0.18.3, =0.0.1, =0.3.2-develop-1171, =1.2.0-pillar-v4.0 and more Source cves: CVE-2026-6402 Source advisor...

@4399ywkf/core (>=5.0.0, <=5.0.32), @all-star/base (>=0.17.0, <=0.18.2) +320 more potentially affected by CVE-2025-30359 +2 more via webpack-dev-server (>=5.0.0, <=5.2.3)

webpack-dev-server NPM version =5.0.0, =5.0.0, =0.17.0, =0.17.0, =0.17.0, =8.0.0-next.2, =18.0.0-beta.3, =18.0.0-beta.3, =18.2.6-RC-1, =18.0.0, =18.0.0-next.0, =1.0.5-beta.4, =1.0.1-beta.1, =0.18.3, =0.0.1, =0.3.2-develop-1171, =1.2.0-pillar-v4.0 and more Source cves: CVE-2025-30359,...

webpack-dev-server vulnerable to cross-origin source code exposure on non-HTTPS origins

Impact When webpack-dev-server is running on a non-HTTPS origin the default, cross-origin requests from malicious websites can load the dev server's JavaScript bundles via tags. The fix introduced in v5.2.1 CVE-2025-30359 relied on Sec-Fetch-Mode and Sec-Fetch-Site request headers to block these...