The server caches query string parameters from the RUNTIME.route.queryString object across different user sessions. This can lead to a user's session incorrectly inheriting query string data from a previous user's session.

Simulation

This behavior can be reproduced in applications that read query string parameters from the __RUNTIME__ variable.

1. Access a store page with a specific query string on machine A. For example: https://www.examplestore.com/sale?targeting=affiliate_A
2. The application running on the page reads the targeting parameter from __RUNTIME__.route.queryString and correctly identifies affiliate_A.
3. On a completely different machine B (and a new, clean session), access the same store page, but without the query string. For example: https://www.examplestore.com/sale
4. The application on machine B reads the targeting parameter from __RUNTIME__.route.queryString.
5. Expected behavior: The __RUNTIME__.route.queryString object should be empty or not contain the targeting parameter, as it was not present in the URL for this session.
6. Actual behavior: Due to server-side caching, the __RUNTIME__.route.queryString object still contains targeting=affiliate_A from machine A's session. The application incorrectly attributes the session on machine B to affiliate_A.

Workaround

Do not use the __RUNTIME__.route.queryString object to read dynamic query string parameters expected to vary between users or sessions (such as affiliate, campaign, or user identifiers). This variable is subject to server-side page caching and is not session-specific. The correct and recommended approach is to read parameters directly from the URL.

• For client-side components (React): Use browser APIs like window.location.search to get the current URL's query string and parse it.
• For server-side rendering (Node.js): Access the query string from the request context (e.g., ctx.query) instead of the __RUNTIME__ object. This ensures that the data is always specific to the user's current request and is not affected by the cache of a previous session.