Next.js Race Condition to Cache Poisoning
Research is free — Hunters explains how the bug works, the root-cause code pattern, how the fix addresses it, and how to test whether a target is affected, in chat. Investigate & write exploit is a paid run — the engine reads the advisory and fix commits, then builds and validates a working proof-of-concept exploit with reproduction steps.
Affected versions
Details
**Summary** We received a responsible disclosure from Allam Rachid (zhero) for a low-severity race-condition vulnerability in Next.js. This issue only affects the **Pages Router** under certain misconfigurations, causing normal endpoints to serve `pageProps` data instead of standard HTML. [Learn more here](https://vercel.com/changelog/cve-2025-32421) **Credit** Thank you to **Allam Rachid (zhero)** for the responsible disclosure. This research was rewarded as part of our bug bounty program.