Modification of assumed-immutable data in i18next - CVE-2026-63402
Published: July 27, 2026
Vulnerability identifier: #VU139486
CSH Severity: Medium
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:L/VA:H/SC:N/SI:N/SA:N/E:P/U:Green
CVE-ID: CVE-2026-63402
CWE-ID: CWE-471
Exploitation vector: Remote access
Exploit availability:
Public exploit is available
Vendor: i18next
Affected software:
i18next
i18next
Detailed vulnerability description
The vulnerability allows a remote attacker to bypass certain security restrictions.
The vulnerability exists due to application does not perform validation of the attacker-controlled data, assuming that data is valid and safe within deepExtend in src/utils.js. A remote user can perform a denial of service (DoS) attack.
How to mitigate CVE-2026-63402
Install updates from vendor's website.