216.73.216.233

CVE-2026-48713

· Published 16/06/2026 00:16 · Modified 16/06/2026 15:46 · Author: The MITRE Corporation

Labels: CVE-2026-48713 2026-06-15CVE-2026-48713CWE-1321[email protected]

Essential information

Published
16/06/2026 00:16
Modified
16/06/2026 15:46
Author
The MITRE Corporation
Creator
The MITRE Corporation
CVSS
9.1 CRITICAL (v3.1)
CISA KEV
No
CWE
CWE-1321
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H

CVSS metrics

Description

Versions prior to 2.6.6 are vulnerable to prototype pollution via crafted missing-key strings when used to persist missing translation keys (e.g. via i18next-http-middleware's missingKeyHandler exposed to untrusted input). Backend.writeFile() splits each queued missing-key string on the configured keySeparator (default .) before calling the internal setPath() walker. The walker (getLastOfPath in lib/utils.js) did not guard against unsafe segments, so a key like "__proto__.polluted" was split into ["__proto__", "polluted"] and walked straight into Object.prototype, allowing an attacker to write arbitrary properties onto the global object prototype. Depending on the host application, polluted prototype properties may cause crashes, corrupted translation behaviour, configuration poisoning, or bypasses of property-based security checks. Applications are affected only if the missingKeyHandler (or another route that forwards untrusted request bodies to i18next.t(..., { ... }) with saveMissing: true) is reachable by untrusted users and the default behaviour of splitting missing-key strings on keySeparator is in use (i.e. keySeparator is not false). Apps that do not expose missing-key persistence to untrusted input are not directly affected through this attack path. This issue has been fixed in version 2.6.6. If developers using the library are unable to upgrade immediately, they should take the following precautions: do not expose i18next-http-middleware's missingKeyHandler to untrusted users (mount it behind authentication, or remove the route), disable missing-key persistence (saveMissing: false, or no backend.create implementation) when accepting writes from untrusted input, and set keySeparator: false in their i18next options to disable backend key splitting (note: this also disables nested translation keys).

NVD status

Status
Undergoing Analysis — CVE has been recently published to the CVE List and has been received by the NVD.
Source
[email protected]
NVD
View on NVD

Affected products (CPE)

ProductCPE
i18next / i18next cpe:2.3:a:i18next:i18next:<2.6.6:*:*:*:*:*:*:*
i18next / i18next cpe:2.3:a:i18next:i18next:2.6.6:*:*:*:*:*:*:*

References