CVE-2026-63402Medium· 5.9▾ TwilightPoC availablei18next 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`.…
▾ Twilight zone — High severity, or a signal on a lesser flaw
impact 32.5 · likelihood 0.1 · exploitation 12
A public proof-of-concept already exists for this vulnerability — see Exploit availability below.
Stakeholder-Specific Vulnerability Categorization from CISA's ADP record at CVE.org: whether exploitation is observed, whether an attack can be automated, and how much of the system is at stake. The CVSS score shown above comes from the assigning CNA record, not NVD.
Exploit-prediction probability, daily snapshots since Nov 5.
Disclosure to exploitation, from the record and what we observed since indexing it.
Disclosed via CVEORG
Last analysed / modified upstream
0.3%
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.
i18next < 26.3.4Refer to the linked advisories for vendor-supplied fixes and affected version ranges.
Connected by shared product, vendor, weakness, or advisory.
CVE-2026-118258Low· 3.7i18next-http-backend: Query-parameter injection through & and = in lng when loadPath/addPath puts {{lng}} in the query string
CVE-2026-115730Low· 3.1i18next-http-backend 4.0.2 Protocol-Relative URL Injection via Namespace in interpolateUrl
CVE-2026-54610Low· 3.3LibreDWG: const-input mutation and crash in bit_TV_to_utf8 error handling
CVE-2026-15195Medium· 6.3apidevtools json-schema-ref-parser pointer.ts Pointer.set prototype pollution
CVE-2026-118780Low· 3.7Forge: verifyCertificateChain() removes trusted CA certificates with the same subject from the CA store
CVE-2026-116674Medium· 6.5systeminformation: Prototype pollution in `networkStats()` via the interface name