The AuthKit library for Next.js provides convenient helpers for authentication and session management using WorkOS & AuthKit with Next.js. In authkit-nextjs version 2.11.0 and below, authenticated responses do not defensively apply anti-caching headers. In environments where CDN caching is enabled, this can result in session tokens being included in cached responses and subsequently served to multiple users. Next.js applications deployed on Vercel are unaffected unless they manually enable CDN caching by setting cache headers on authenticated paths. Patched in authkit-nextjs 2.11.1, which applies anti-caching headers to all responses behind authentication.
The code uses a cache that contains sensitive information, but the cache can be read by an actor outside of the intended control sphere.