CVE-2026-41692: I18nextify /data: URL Schemes Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-6457-mxpq-4fqq",
  "modified" : "2026-05-11T13:29:23Z",
  "published" : "2026-04-22T17:42:24Z",
  "aliases" : [ "CVE-2026-41692" ],
  "summary" : "i18nextify has DOM XSS via javascript:/data: URL schemes in translated href/src attributes",
  "details" : "### Summary\n\nVersions of `i18nextify` prior to 4.0.8 substitute `{{key}}` interpolation tokens inside `src` and `href` attribute values with the raw string returned by `i18next.t()`. The substitution logic in `src/localize.js` (`replaceInside` handler around line 122) only guards against a duplicated `http://` origin prefix — it does not validate the URL scheme of the substituted value. A translated value such as `javascript:alert(1)` or `data:text/html,<script>...</script>` is applied unchanged to the live DOM attribute.\n\n### Impact\n\nWhen an attacker can influence the content of a translation file or the translation-backend response — compromised translation CDN, user-contributed locales, MITM on a plain-HTTP backend, write access to the translation JSON — they can:\n\n- Set any `href` on an anchor to a `javascript:` URI, executing arbitrary JavaScript when the victim clicks the link.\n- Set any `src` on `<iframe>`, `<object>`, or `<embed>` to a `data:text/html` URI containing a full script payload that runs in the page's origin.\n- Use `vbscript:` on legacy IE installations or `file:` for local-resource navigation attacks.\n\nThis path is distinct from the general i18nextify design that intentionally renders HTML from translations — href/src schemes are narrow and attack-specific, and no legitimate translation needs `javascript:` or `data:`. The fix therefore blocks these schemes outright without changing other behaviour.\n\n### Also fixed in 4.0.8\n\n- **`debug` / `saveMissing` URL-parameter substring match.** The previous detection `window.location.search.indexOf('debug=true') > -1` matched the substring anywhere in the query string. A URL like `?nosaveMissing=true` silently enabled `saveMissing` mode, causing the victim's browser to POST every unknown translation key to the configured `addPath` — a form of CSRF-style abuse of missing-key reporting. `?track_debug=true` enabled verbose debug logging, leaking i18next internals to the console. Now uses `URLSearchParams` for exact parameter matching.\n- **Optional `sanitize(html, ctx)` hook.** The library's core purpose is to render HTML from translations — a behaviour that is safe only when the translation source is fully trusted. Applications with partially-trusted sources (user-contributed locales, third-party CDN, MITM-exposed HTTP backend) can now wire a sanitizer (e.g. DOMPurify) via `i18next.options.sanitize`. Defaults to pass-through to preserve existing behaviour for the main use case.\n\n### Affected versions\n\nAll versions of `i18nextify` prior to **4.0.8**.\n\n### Patch\n\nFixed in **4.0.8**. The URL-scheme blocklist is `^\\s*(javascript|data|vbscript|file)\\s*:` (case-insensitive) applied to each translated value before it is joined back into the `href`/`src` attribute. Values matching the blocklist are replaced with an empty string so the attribute becomes harmless rather than leaving the attacker's URL in place.\n\n### Workarounds\n\nNo workaround short of upgrading. If you cannot upgrade immediately, audit every translation file for `javascript:`, `data:`, `vbscript:`, and `file:` prefixes in any value that may reach an `href`/`src` position, and restrict translation-file write access to trusted operators. Serving translations over HTTPS and pinning the translation backend to an internal origin reduce the MITM surface.\n\n### Credits\n\nDiscovered via an internal security audit of the i18next ecosystem.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:L/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "npm",
      "name" : "i18nextify"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "4.0.8"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/i18next/i18nextify/security/advisories/GHSA-6457-mxpq-4fqq"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-41692"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/i18next/i18nextify/commit/16f23dbcdcf893673587f7a03355bf7ce0a0e49e"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/i18next/i18nextify"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-79", "CWE-94" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-04-22T17:42:24Z",
    "nvd_published_at" : "2026-05-07T21:16:29Z"
  }
}