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 respon…
Exact source revision recorded 27 Oct 2026 10:10:19 UTC. It does not establish the source's current position. Latest evidence.
nvd · CVE-2026-41683
Publishedi18next-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.
NVD analysis and CPE criteria are source context, not proof that a package or your environment is affected. Complete affected data, logical configurations and SSVC are retained in the original JSON.
Source analysis status: Deferred
Weakness classifications: CWE-79 · CWE-113
Original publisher date fields
published: 2026-05-08T16:16:11.320
lastModified: 2026-10-26T18:10:00.173
- Source published
- 8 May 2026 16:16:11 UTC
- Source modified
- 26 Oct 2026 18:10:00 UTC
- Observed here
- 27 Oct 2026 10:10:19 UTC
- Source terms
- NIST NVD usage terms; underlying source attribution retained
Original source record · Cite this exact observation · Complete original publisher JSON
This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: nvd · NIST NVD usage terms; underlying source attribution retained. Source text is retained; field grouping and change labels are provided by ChangeIntel.
CVSS 3.1 · [email protected] · Secondary · 8.6 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:L