Modification of Assumed-Immutable Data (MAID) Affecting node-i18next package, versions *
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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- published31 Oct 2026
- disclosed30 Oct 2026
Introduced: 30 Oct 2026
NewCVE-2026-63402 (opens in a new tab)How to fix?
There is no fixed version for Debian:unstable node-i18next.
NVD Description
Note: Versions mentioned in the description apply only to the upstream node-i18next package and not the node-i18next package as distributed by Debian.
See How to fix? for Debian:unstable relevant fixed versions and status.
i18next is an internationalization framework for JavaScript. Prior to version 26.3.4, deepExtend in src/utils.js checks property existence with the in operator and recurses into inherited built-ins reached through Object.prototype. An application must explicitly pass attacker-controlled resource data to addResourceBundle(lng, ns, data, deep, overwrite) with both deep: true and overwrite: true. Source keys such as hasOwnProperty, toString and valueOf can then select shared inherited built-in function objects, and a nested value can overwrite a property of those objects process-wide. For example, making Object.prototype.hasOwnProperty.call non-callable causes subsequent uses, including i18next internals, to throw TypeError, resulting in unrecoverable denial of service and limited integrity impact. The __proto__/constructor guard does not prevent this mechanism because the corruption target is an inherited built-in function rather than the prototype object itself. Default calls without deep merging or with overwrite falsy are unaffected, and no standard i18next backend or integration uses the vulnerable configuration. This issue is distinct from the setPath/key-walking prototype-pollution flaws in i18next-fs-backend (CVE-2026-48713) and i18next-http-middleware (CVE-2026-48714). This issue is fixed in version 26.3.4.