GHSA-4c35-wcg5-mm9h: next-intl has prototype pollution with `experimental.messages.precompile` via attacker-controlled translation catalog keys
setNestedProperty in packages/next-intl/src/extractor/utils.tsx walks a dotted key path and assigns the final value without blocking the reserved keys __proto__, constructor, or prototype. When the next-intl Next.js plugin is configured with experimental.messages and messages.precompile: true, a JSON translation catalog containing a top‑level __proto__ key causes setNestedProperty(result, '__proto__.isAdmin', compiledMessage) to assign onto Object.prototype, polluting every object in the running build process.
References
Code Behaviors & Features
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