Answer in brief
CVE-2026-14631 records a Medium severity (CVSS 5.3) vulnerability in webpack-dev-server vulnerable to denial of service via a malformed Host or Origin header. The current sources do not mark it as known exploited. The current feed maps webpack-dev-server/webpack-dev-server (generic), webpack-dev-server (npm). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 5.3. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps webpack-dev-server/webpack-dev-server (generic), webpack-dev-server (npm). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| webpack-dev-server/webpack-dev-servergeneric | >=0 <5.2.6 | 5.2.6 |
| webpack-dev-servernpm | >=0 <5.2.6 | 5.2.6 |
Published upstream
Jul 3, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Sep 10, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Jul 3, 2026
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.
Quoted source text, attributed separately from HOL analysis.