What is CVE-2026-48713?

CVE-2026-48713 is a critical-severity vulnerability in I18next I18next-fs-backend, classified under Improperly Controlled Modification of Object Prototype Attributes (Prototype Pollution). CVSS score: 9.1/10. Published 2026-06-15.

How severe is CVE-2026-48713?

Critical severity. CVSS v3 base score is 9.1 out of 10.

Prototype Pollution in I18next I18next-fs-backend

CVE-2026-48713

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.writeFil…

Vulnerability class: Prototype Pollution

CVSS v3 metric

CVSS v3 base score 9.1 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H.

Affected products

I18next I18next-fs-backend — versions < 2.6.6

Weakness classification (CWE)

CWE-1321 — Improperly Controlled Modification of Object Prototype Attributes (Prototype Pollution)

References

security-advisories@github.com (x_refsource_CONFIRM)
security-advisories@github.com (x_refsource_MISC)

Frequently asked questions

What is CVE-2026-48713?: CVE-2026-48713 is a critical-severity vulnerability in I18next I18next-fs-backend, classified under Improperly Controlled Modification of Object Prototype Attributes (Prototype Pollution). CVSS score: 9.1/10. Published 2026-06-15.
How severe is CVE-2026-48713?: Critical severity. CVSS v3 base score is 9.1 out of 10.