Detections
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SCA: security update for i18next-fs-backend (GHSA-2933-q333-qg83)

critical Tenable Cloud Security Plugin ID 443972

Description

There are packages installed that are affected by a vulnerability referenced in the following CVE:

 - 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).
 (CVE-2026-48713)

Solution

Update the i18next-fs-backend library and its related packages to version 2.6.6 or later.

See Also

https://github.com/advisories/GHSA-2933-q333-qg83

Plugin Details

Severity: Critical

ID: 443972

Version: Revision 1.2

Type: Local

Family: SCA Checks

Published: 6/26/2026

Updated: 7/2/2026

Supported Sensors: Tenable Cloud Security, Tenable Self-Hosted Container Security

Risk Information

VPR

Risk Factor: High

Score: 7

Percentile: 98.3

Vendor

Vendor Severity: Critical

CVSS v2

Risk Factor: High

Base Score: 9.4

Temporal Score: 7

Vector: CVSS2#AV:N/AC:L/Au:N/C:N/I:C/A:C

CVSS Score Source: CVE-2026-48713

CVSS v3

Risk Factor: Critical

Base Score: 9.1

Temporal Score: 7.9

Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H

Temporal Vector: CVSS:3.0/E:U/RL:O/RC:C

Vulnerability Information

Exploit Ease: No known exploits are available

Patch Publication Date: 6/25/2026

Vulnerability Publication Date: 6/15/2026

Reference Information

CVE: CVE-2026-48713