What is CVE-2025-32421?

CVE-2025-32421 is a low-severity vulnerability in Vercel Next.js, classified under Concurrent Execution using Shared Resource with Improper Synchronization (Race Condition). CVSS score: 3.7/10. Published 2025-05-14.

How severe is CVE-2025-32421?

Low severity. CVSS v3 base score is 3.7 out of 10.

Is CVE-2025-32421 known to be exploited?

4 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.

Vulnerability in Vercel Next.js

CVE-2025-32421

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.

Vulnerability class: Race Condition

Published 2025-05-14 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 3.7 (Low). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N.

EPSS exploit prediction

EPSS: 0.008 (53.9th percentile), scored 2026-09-30.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 54th percentile — 53.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.008 · newest: 0.008 · change: 0.000

Affected products

Vercel Next.js — versions < 14.2.24, >= 15.0.0, < 15.1.6

Weakness classification (CWE)

CWE-362 — Concurrent Execution using Shared Resource with Improper Synchronization (Race Condition)

Public proof-of-concept exploits

References

github.com/vercel/next.js/security/advisories/GHSA-qpjv-v59x-3qc4 (Vendor Advisory)
vercel.com/changelog/cve-2025-32421 (Vendor Advisory)

Frequently asked questions

What is CVE-2025-32421?: CVE-2025-32421 is a low-severity vulnerability in Vercel Next.js, classified under Concurrent Execution using Shared Resource with Improper Synchronization (Race Condition). CVSS score: 3.7/10. Published 2025-05-14.
How severe is CVE-2025-32421?: Low severity. CVSS v3 base score is 3.7 out of 10.
Is CVE-2025-32421 known to be exploited?: 4 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.