{"id":"GHSA-m28w-2pqf-7qgj","summary":"webpack-dev-server vulnerable to denial of service via a malformed Host or Origin header","details":"### Impact\n\nAn unauthenticated peer that can reach the `webpack-dev-server` process can terminate it by sending either a normal HTTP request with a malformed `Host` header, or a WebSocket upgrade to the default `/ws` endpoint with a malformed `Origin` header. The malformed header triggers an uncaught exception in the host-validation path and crashes the dev server process.\n\n### Patches\n\nFixed in `webpack-dev-server` 5.2.6 by treating malformed `Host` and `Origin` header values as invalid rather than throwing (see [PR #5699](https://github.com/webpack/webpack-dev-server/pull/5699)).\n\n### Workarounds\n\nKeep the dev server bound to `localhost` (the default) and do not expose it to untrusted networks.","aliases":["CVE-2026-14631"],"modified":"2026-08-24T00:37:03.998443457Z","published":"2026-07-20T22:02:31Z","database_specific":{"github_reviewed":true,"github_reviewed_at":"2026-07-20T22:02:31Z","nvd_published_at":"2026-07-03T18:16:24Z","cwe_ids":["CWE-20","CWE-248"],"severity":"MODERATE"},"references":[{"type":"WEB","url":"https://github.com/webpack/webpack-dev-server/security/advisories/GHSA-m28w-2pqf-7qgj"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-14631"},{"type":"WEB","url":"https://github.com/webpack/webpack-dev-server/pull/5699"},{"type":"WEB","url":"https://github.com/webpack/webpack-dev-server/commit/f21ed0f44aceb6132abb591ee8b60d770b6e489f"},{"type":"WEB","url":"https://cna.openjsf.org/security-advisories.html"},{"type":"PACKAGE","url":"https://github.com/webpack/webpack-dev-server"}],"affected":[{"package":{"name":"webpack-dev-server","ecosystem":"npm","purl":"pkg:npm/webpack-dev-server"},"ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"5.2.6"}]}],"database_specific":{"last_known_affected_version_range":"\u003c= 5.2.5","source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/07/GHSA-m28w-2pqf-7qgj/GHSA-m28w-2pqf-7qgj.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L"}]}