CVE-2026-41683: i18next-http-middleware · Cross-site Scripting
Affects i18next-http-middlewareSource CVE Database V5
Not known to be exploited · CVSS 8.6 High : upgrade to 3.9.3 soon.
Data as of 30 Oct 2026, 11:52 UTC
- EPSS
- 0.3% chance of exploitation in 30 days – higher than 25% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 3.9.3
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:LExploitation evidence
Disclosed: evidence found.
CVE published 8 May 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 30 Oct 2026.
What to do
Upgrade i18next-http-middleware to 3.9.3.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| i18nexti18next-http-middleware | Affected
| Fixed in
|
npmi18next-http-middlewarepkg:npm/i18next-http-middlewareOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
This vulnerability is fixed in i18next-http-middleware version 3.9.3. Users should upgrade to version 3.9.3 or later to remediate this issue. No official remediation level is provided beyond this patch. Patch status is confirmed by the vendor advisory stating the fix is included in version 3.9.3. If upgrading is not immediately possible, carefully validate and sanitize user-controlled language inputs to prevent injection of CRLF sequences, though this is a temporary measure.
Description
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.