{"cve":"CVE-2026-6402","nvd":{"published":"2026-05-12T09:16:55.640","modified":"2026-06-17T11:00:47.087","status":"Analyzed","description":"webpack-dev-server versions up to and including 5.2.3 are vulnerable to cross-origin source code exposure when serving over a non-potentially trustworthy origin such as plain HTTP. The previous fix relied on the Sec-Fetch-Mode and Sec-Fetch-Site request headers, which browsers omit for non-trustworthy origins, allowing a malicious site to load the bundled source as a script and read it across origins. Impact: an attacker controlling a website visited by a developer running webpack-dev-server can recover the application source code when the dev server runs over HTTP at a guessable host and port. Chromium based browsers from Chrome 142 onward are not affected due to local network access restrictions. Upgrade to webpack-dev-server 5.2.4 or later, which sets Cross-Origin-Resource-Policy: same-origin on responses.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N","score":6.5},"cwes":["CWE-749"],"references":["https://cna.openjsf.org/security-advisories.html","https://github.com/webpack/webpack-dev-server/security/advisories/GHSA-79cf-xcqc-c78w"],"products":["webpack.js:webpack-dev-server"],"source":"nvd","synced_at":"2026-10-19T22:33:55.586217763+00:00"},"epss":{"cve":"CVE-2026-6402","score":0.00291,"percentile":0.21732,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-79cf-xcqc-c78w","url":"https://osv.dev/vulnerability/GHSA-79cf-xcqc-c78w","summary":"webpack-dev-server vulnerable to cross-origin source code exposure on non-HTTPS origins","modified":"2026-09-10T03:50:46.202661971Z","packages":[{"ecosystem":"npm","name":"webpack-dev-server","purl":"pkg:npm/webpack-dev-server","ranges":["<5.2.4"],"fixed":["5.2.4"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}