CVE-2026-114142: toml-node: Prototype pollution: parsing a TOML document can write to Object.prototype

CVE-2026-63376 described prototype pollution through proto key-path desynchronization and was fixed in 4.1.2 by rewriting the path bookkeeping and adding an ownedContainers WeakSet. The desynchronization is still reachable, spelled with a quote character instead of a dot, and the owned-container check is not applied on the path that matters.

A four-line TOML document parsed with toml.parse() writes a property onto Object.prototype, where it is visible to every object in the process — including objects produced by unrelated libraries.