Next.js security posture
While Next.js provides robust defaults like automatic XSS protection and built-in CSRF measures for certain hooks, complex Server Action implementations and custom API routes often introduce critical security gaps in production environments.
2 linked rules in the directory.
Top risks for this stack
00 critical07 high
Next.js has a Middleware / Proxy bypass in App Router applications via segment-prefetch routes - Incomplete Fix Follow-UpHIGH
May 2026
Rule coverage exists — verify in Composer export.
Next.js vulnerable to Denial of Service via connection exhaustion in applications using Cache ComponentsHIGH
May 2026
Rule coverage exists — verify in Composer export.
Next.js vulnerable to cache poisoning in React Server Component responsesMEDIUM
May 2026
Rule coverage exists — verify in Composer export.
Next.js has a Middleware / Proxy bypass in App Router applications via segment-prefetch routesHIGH
May 2026
Rule coverage exists — verify in Composer export.
Next.js has a Middleware / Proxy bypass through dynamic route parameter injectionHIGH
May 2026
Rule coverage exists — verify in Composer export.
Facebook React has a Denial of Service Vulnerability in React Server ComponentsHIGH
May 2026
Rule coverage exists — verify in Composer export.
React Server Components have a Denial of Service VulnerabilityHIGH
Apr 2026
Rule coverage exists — verify in Composer export.
Next.js: Unbounded postponed resume buffering can lead to DoSHIGH
Mar 2026
Rule coverage exists — verify in Composer export.
What the framework handles
FeatureStatus
XSS PreventionBUILT-IN
Route ProtectionMANUAL CFG
CORS PolicyMANUAL CFG
Header SecurityBUILT-IN
Environment IsolationBUILT-IN