{"id":"CVE-2026-6402","state":"PUBLISHED","title":"webpack-dev-server vulnerable to cross-origin source code exposure on non-HTTPS origins","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.","publishedAt":"2026-05-12T07:45:21.253Z","updatedAt":"2026-05-12T13:00:06.847Z","severity":{"score":5.3,"label":"Medium","version":"3.1","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:N/A:N","source":"openjs"},"assigner":"openjs","products":["webpack-dev-server webpack-dev-server"],"affected":[{"vendor":"webpack-dev-server","product":"webpack-dev-server","packageURL":"pkg:npm/webpack-dev-server","defaultStatus":"unaffected","versions":[{"version":"0","status":"affected","lessThan":"5.2.4","versionType":"semver"},{"version":"5.2.4","status":"unaffected","versionType":"semver"}]}],"references":["https://github.com/webpack/webpack-dev-server/security/advisories/GHSA-79cf-xcqc-c78w","https://cna.openjsf.org/security-advisories.html"],"weaknesses":["CWE-749"],"ingestedAt":"2026-10-29T20:12:49.727Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/6xxx/CVE-2026-6402.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-6402","state":"PUBLISHED","datePublished":"2026-05-12T07:45:21.253Z","dateUpdated":"2026-05-12T13:00:06.847Z","assignerShortName":"openjs","assignerOrgId":"ce714d77-add3-4f53-aff5-83d477b104bb","dateReserved":"2026-04-15T20:35:29.271Z"},"containers":{"cna":{"title":"webpack-dev-server vulnerable to cross-origin source code exposure on non-HTTPS origins","descriptions":[{"lang":"en","value":"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."}],"affected":[{"vendor":"webpack-dev-server","product":"webpack-dev-server","packageURL":"pkg:npm/webpack-dev-server","defaultStatus":"unaffected","versions":[{"version":"0","status":"affected","lessThan":"5.2.4","versionType":"semver"},{"version":"5.2.4","status":"unaffected","versionType":"semver"}]}],"references":[{"url":"https://github.com/webpack/webpack-dev-server/security/advisories/GHSA-79cf-xcqc-c78w"},{"url":"https://cna.openjsf.org/security-advisories.html"}],"metrics":[{"format":"CVSS","cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:N/A:N","baseScore":5.3,"baseSeverity":"MEDIUM"},"scenarios":[{"lang":"en","value":"GENERAL"}]}],"problemTypes":[{"descriptions":[{"cweId":"CWE-749","lang":"en","description":"CWE-749: Exposed Dangerous Method or Function","type":"CWE"}]}],"providerMetadata":{"shortName":"openjs","orgId":"ce714d77-add3-4f53-aff5-83d477b104bb","dateUpdated":"2026-05-12T07:45:21.253Z"},"credits":[{"lang":"en","type":"reporter","value":"sapphi-red"},{"lang":"en","type":"remediation developer","value":"Ulises Gascón"},{"lang":"en","type":"remediation developer","value":"Sebastian Beltran"},{"lang":"en","type":"remediation reviewer","value":"Alexander Akait"}],"x_generator":{"engine":"cve-kit 1.0.0"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-05-12T12:57:17.986993Z","id":"CVE-2026-6402","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-05-12T13:00:06.847Z"}}]}}}