{"id":80588,"date":"2026-06-15T19:46:35","date_gmt":"2026-06-15T16:16:35","guid":{"rendered":"https:\/\/afaghhosting.net\/blog\/cve-2026-9595-webpack-dev-server-vulnerable-to-hmr-websocket-interception-via-permissive-user-proxies\/"},"modified":"2026-06-15T19:46:35","modified_gmt":"2026-06-15T16:16:35","slug":"cve-2026-9595-webpack-dev-server-vulnerable-to-hmr-websocket-interception-via-permissive-user-proxies","status":"publish","type":"post","link":"https:\/\/afaghhosting.net\/blog\/cve-2026-9595-webpack-dev-server-vulnerable-to-hmr-websocket-interception-via-permissive-user-proxies\/","title":{"rendered":"CVE-2026-9595 &#8211; webpack-dev-server vulnerable to HMR WebSocket interception via permissive user proxies"},"content":{"rendered":"<p>CVE ID :CVE-2026-9595<\/p>\n<p>  Published : June 15, 2026, 4:16 p.m. | 1\u00a0hour, 25\u00a0minutes ago<\/p>\n<p>  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&#8217;s own HMR WebSocket and forwards it to the proxy target. This leaks the browser&#8217;s cookies and Origin header to the backend, bypasses the dev server&#8217;s Host\/Origin validation, and corrupts the HMR socket (both HMR and the proxy end up writing to the same socket).<\/p>\n<p>Patches: Fixed in webpack-dev-server@5.2.5.<\/p>\n<p>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.<\/p>\n<p>  Severity: 5.3 | MEDIUM<\/p>\n<p>  Visit the link for more details, such as CVSS details, affected products, timeline, and more&#8230;\u00a0<\/p>\n","protected":false},"excerpt":{"rendered":"<p>CVE ID :CVE-2026-9595 Published : June 15, 2026, 4:16 p.m. | 1\u00a0hour, 25\u00a0minutes ago 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&#8217;s own HMR WebSocket and forwards it to the proxy target. This leaks the browser&#8217;s cookies and Origin header &hellip;<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[26],"tags":[],"class_list":["post-80588","post","type-post","status-publish","format-standard","hentry","category-vulnerability"],"_links":{"self":[{"href":"https:\/\/afaghhosting.net\/blog\/wp-json\/wp\/v2\/posts\/80588","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/afaghhosting.net\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/afaghhosting.net\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/afaghhosting.net\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/afaghhosting.net\/blog\/wp-json\/wp\/v2\/comments?post=80588"}],"version-history":[{"count":0,"href":"https:\/\/afaghhosting.net\/blog\/wp-json\/wp\/v2\/posts\/80588\/revisions"}],"wp:attachment":[{"href":"https:\/\/afaghhosting.net\/blog\/wp-json\/wp\/v2\/media?parent=80588"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/afaghhosting.net\/blog\/wp-json\/wp\/v2\/categories?post=80588"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/afaghhosting.net\/blog\/wp-json\/wp\/v2\/tags?post=80588"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}