Medium 5.3Published Jul 3, 2026

CVE-2026-14631webpack-dev-server vulnerable to denial of service via a malformed Host or Origin header

Updated under an hour ago (Oct 27, 2026, 9:10 PM ET)

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No exploitation reported and no EPSS estimate yet.

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Every CVE for webpack-dev-server

Exploited in the last 30 days

webpack-dev-server versions 5.2.5 and earlier terminate the whole Node.js process when an unauthenticated peer sends 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 value causes an uncaught exception in the host-validation path and crashes the dev server. Impact is limited to availability of the development server, no data disclosure, no code execution. Patches: upgrade to webpack-dev-server 5.2.6. Workarounds: keep the dev server bound to localhost (the default) and do not expose it to untrusted networks.

CVSS: 5.3 MEDIUM (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Weakness (CWE): CWE-20, CWE-248
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: openjs
NVD analysis: Analyzed
Record last updated: Jul 6, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

webpack-dev-server webpack-dev-server webpack_dev_server:webpack_dev_server (from the name)	before 5.2.6; 5.2.6 not affected	CNA record
webpack.js webpack-dev-server webpack.js:webpack-dev-server	before 5.2.6	NVD

References

References

https://github.com/webpack/webpack-dev-server/security/advisories/GHSA-m28w-2pqf-7qgj	mitigation, vendor-advisory, patch
https://cna.openjsf.org/security-advisories.html	third-party-advisory

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.