CVE-2025-32421: vercel next.js Race Condition

Vulnerability summary

CVE-2025-32421 is a low (CVSS 3.7) Race Condition vulnerability in vercel next.js. EPSS estimates a 0.80% chance of exploitation in the next 30 days, higher than 56% of scored vulnerabilities.

Timeline

1. 14-05-2025
   PublishedVulnerability first disclosed.
2. 15-05-2025
   Last modifiedVulnerability information updated.

Description

Next.js is a React framework for building full-stack web applications. Versions prior to 14.2.24 and 15.1.6 have a race-condition vulnerability. This issue only affects the Pages Router under certain misconfigurations, causing normal endpoints to serve `pageProps` data instead of standard HTML. This issue was patched in versions 15.1.6 and 14.2.24 by stripping the `x-now-route-matches` header from incoming requests. Applications hosted on Vercel's platform are not affected by this issue, as the platform does not cache responses based solely on `200 OK` status without explicit `cache-control` headers. Those who self-host Next.js deployments and are unable to upgrade immediately can mitigate this vulnerability by stripping the `x-now-route-matches` header from all incoming requests at the content development network and setting `cache-control: no-store` for all responses under risk. The maintainers of Next.js strongly recommend only caching responses with explicit cache-control headers.

• CWE-362Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')The product contains a concurrent code sequence that requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence operating concurrently.