Advisories for Npm/Next-Intl package

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.

Applications using the next-intl middleware with localePrefix: 'as-needed' could construct URLs where path handling and the WHATWG URL parser resolved a relative redirect target to another host (e.g. scheme-relative // or control characters stripped by the URL parser), so the middleware could redirect the browser off-site while the user still started from a trusted app URL.

Applications using the next-intl middleware with localePrefix: 'as-needed' could construct URLs where path handling and the WHATWG URL parser resolved a relative redirect target to another host (e.g. scheme-relative // or control characters stripped by the URL parser), so the middleware could redirect the browser off-site while the user still started from a trusted app URL.