GHSA-m28w-2pqf-7qgj: webpack-dev-server vulnerable to denial of service via a malformed Host or Origin header

mediumCVSS 5.3CVE-2026-14631

Impact An 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. Patches Fixed in webpack-dev-server 5.2.6 by treating malformed Host and Origin header values as invalid rather than throwing (see PR #5699). Workarounds Keep the dev server bound to localhost (the default) and do not expose it to untrusted networks.

Details

Source: GitHub Security Advisories (INTL · database · site)
Severity: medium — CVSS 5.3
Published: 2026-07-20
Last updated: 2026-07-20
Exploitation: Not in CISA KEV at last sync

Original advisory: https://github.com/advisories/GHSA-m28w-2pqf-7qgj

Exploitation outlook

EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.

Low exploitation riskCVE-2026-146310.40% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 33% of all scored CVEs.

Referenced CVEs

CVE	CSIRTS overview	External
CVE-2026-14631	coverage & exploitation status	NVD · CVE.org

Same CVEs, other sources

How other CERTs, PSIRTs and databases cover the vulnerabilities in this advisory.

mediumCVE-2026-14631: webpack-dev-server versions 5.2.5 and earlier terminate the whole Node.js process when an unau…nvd

GHSA-m28w-2pqf-7qgj: webpack-dev-server vulnerable to denial of service via a malformed Host or Origin header

Details

Exploitation outlook

Referenced CVEs

Same CVEs, other sources

More from GitHub Security Advisories