CVE-2026-41683
CVE-2026-41683 · HTTP response splitting and DoS in i18next-http-middleware via unsanitised Content-Language header
This page contains facts from public vulnerability sources. Check the original advisory before updating.
i18next-http-middleware is a middleware to be used with Node.js web frameworks like express or Fastify and also for Deno. Prior to version 3.9.3, i18next-http-middleware wrote user-controlled language values into the Content-Language response header after passing them through utils.escape(), which is an HTML-entity encoder that does not strip carriage return, line feed, or other control characters. When the application used an older i18next (< 19.5.0) that still exercised the backward-compatibility fallback at LanguageDetector.js:100 or otherwise produced a raw detected value, CRLF sequences in the attacker-controlled lng parameter reached res.setHeader('Content-Language', ...) verbatim. This issue has been patched in version 3.9.3.
CVSS 8.6 · High · EPSS 0.3% · Fix available
- Published
- Updated
Stack: node
Affected products and versions
i18next-http-middleware
- Versions
- < 3.9.3: Affected
No fix published
i18next-http-middleware npm
- Affected ranges
- SEMVER: < 3.9.3
Update to 3.9.3