Next.js
Published reports for this stack, with severity, affected version, and a direct path into each diagnostic.
The default `use cache` handler stores `streamToBuffer` results that may be small slices of a shared Buffer pool slab. Long-lived cache entries therefore retain whole pool slabs (64 KiB on Node 26) while the LRU only counts the slice's bytes, causing actual memory usage to exceed `cacheMaxMemorySize` by up to 22x.
When cacheComponents is enabled, the export worker serializes the entire batch of static pages' resume data caches into a single IPC message, exceeding Node's maximum string length. process.send throws RangeError: Invalid string length, which becomes an unhandledRejection, leaving the parent waiting indefinitely and causing the build to hang at 'Generating static pages'.
Next.js 16.2.0 and later respond with a 500 Internal Server Error when receiving an OPTIONS * request, whereas earlier versions correctly returned 400 Bad Request or another valid response. This regression affects both development and production servers.
Next.js cacheComponents span-creation exemption is applied after instrumentation.register() returns, but @vercel/otel FetchInstrumentation captures a concrete Tracer during register(); subsequent outgoing HTTP requests in prerender create spans through that unpatched tracer and trip the sync-IO guard, producing a Math.random() prerender error.
When a CSS file is imported by both a page and a component loaded with next/dynamic and kept mounted via _app, the stylesheet link is incorrectly marked with data-n-p and removed during client-side navigation. This happens because the dynamic CSS manifest is not loaded correctly in the route module and not passed to _document.
Regression in Next.js 16.0.3: detached-flush child spawned on dev server shutdown hangs after submitting telemetry when next.config leaves a live handle, causing orphaned processes to accumulate and consume large memory/CPU.
When using Next.js 16 with Turbopack (default bundler), importing a native Node addon (built with napi-rs) from a separate package in a pnpm workspace during server-side prerendering results in `TypeError: (void 0) is not a function`. The package is added to `serverExternalPackages`, but Turbopack still bundles or mishandles the native module, causing the imported binding to be undefined.
Manual mocks in Jest are no longer resolved automatically after upgrading to Next.js 13.2.4; the next/jest preset appears to have broken Jest's default __mocks__ lookup.
Next.js App Router client-side Link navigation to a route whose shared layout calls redirect triggers infinite RSC fetch loop; direct destination navigation works. Reproduced on Next 15.1.7 through 16.4.0-canary.57 with both webpack and Turbopack.
With pnpm v11's enableGlobalVirtualStore enabled, node_modules/next is a symlink to a global store outside the project root. Turbopack's filesystem resolution restricts access to the project root, causing 'Couldn't find the Next.js package' in dev mode. Webpack works; this is a Turbopack-specific limitation.
In Next.js 16.3.0 and later with optimisticRouting enabled by default, navigation from a dynamic segment to another dynamic route can fail to reset scroll position. This occurs when the app has a root parallel slot with a catch-all page returning null, alongside a sibling dynamic route. Predicted route trees reify stale params, causing a server mismatch and retry that consumes the scroll-ref on an empty catch-all leaf, so the new page retains the previous scroll offset.
When cacheComponents is true and htmlLimitedBots matches all bots, using runtime data (e.g. await connection()) inside generateMetadata causes Next.js 16 dev server to log 'did not produce a static shell and Next.js was unable to determine a reason', disrupting development and potentially affecting build/start.
In Next.js 15.5.4, metadata defined via 'export const metadata' is incorrectly rendered inside <body> instead of <head>, breaking Open Graph, Twitter Cards, and SEO. Downgrading to 15.2.4 restores correct behavior.
When reactCompiler and turbopackRustReactCompiler are enabled, the Rust React Compiler runs in the preprocess stage before user-registered swcPlugins, so macro plugins like @lingui/swc-plugin see compiler-hoisted JSX and emit incorrect message IDs, causing silent translation fallback and client/server mismatch.
revalidateTag or revalidatePath called after a Route Handler returns a streaming Response is queued but never executed, causing stale cache entries with no warning.
When configuring Turbopack rules to treat `.css?url` imports as asset type, importing from a Server Component fails with 'css client asset is not css chunk placeable'. The same configuration works from Client Components and for other asset types like SVG.
Clicking a client-side <Link> to a route that calls redirect() never navigates and spins at ~100% CPU when the route builds as fully dynamic (ƒ) under cacheComponents=true. The redirect is caught by RedirectBoundary but never commits, so router.replace is never called. Direct visits work; only production client navigations are affected.
Since Next.js 16.3.0, the published .d.ts files reference global type names URLPatternInput, URLPatternOptions, and URLPattern generic parameters that are only available in TypeScript 6.0+. This causes TypeScript 5.x users with skipLibCheck: false to encounter TS2304 errors in next/dist/server/web/spec-extension/url-pattern.d.ts, breaking typechecking for any project that types its next.config.ts.
Next.js 16.4+ strict route matching incorrectly treats a parallel slot catch-all from one route group as part of routes in sibling groups, causing valid pages to be reported as unmatched and failing dev/production webpack builds.
When a navigation clicks a Link during an in-flight prefetch, a pending segment-cache entry is passed to React as a plain promise. In partial or rejected prefetches the promise resolves to null, causing React to commit an empty segment and drop the document title.
When `outputFileTracingIncludes` is configured, the include-glob walk traverses the entire tracing root and follows symlinks without robust cycle detection. In legal pnpm workspaces where a package nested inside another declares its ancestor as dependency, this creates a self-embedding symlink chain that triggers ELOOP and fails the build.
Turbopack emits the same async-loader module ID with different factories depending on chunk availability. The runtime's first-wins installation causes order-dependent behavior, leading to intermittent dynamic import failures: 'module factory is not available'.
Next.js builds produce different file hashes for the same source code, caused by non-deterministic ordering of CSS modules during webpack compilation, affecting static export reproducibility.
Next.js dev server leaks memory when a route handler executes an infinite async loop, eventually crashing the process. Production build and plain Node.js do not exhibit this issue.
When a modal is opened via interception over a page that is itself interceptable, performing a router.refresh() or revalidatePath causes the background route refresh request to incorrectly include the Next-Url header, leading to an intercepted response and an MPA fallback, resulting in a full page load and loss of client state.
When using MapLibre GL v6 with Next.js Turbopack, the generated worker file contains an import for 'maplibre-gl-shared-dev.mjs', but the emitted file has a hash suffix, causing the worker to fail with 'Worker failed to load'.
When prefetching the index page of an optional catch-all dynamic route, the client caches the __PAGE__ entry under a fallback slug. Subsequent navigation to a sibling dynamic path reuses this cached entry without issuing a new request, causing the wrong page content to be displayed.
In Next.js production builds (App Router), router.refresh() fails to trigger a server round-trip when the current page was streamed and the URL contains a query string. This causes stale UI after mutations on filtered list pages, with no fetch initiated. The issue is present across multiple versions, with 16.2.12 only affected for query-string URLs, and 16.3.5+ affected for all streamed pages. A fix requires forcing cache invalidation for the current URL during refresh.
Next.js dev server (Turbopack) fails to match routes that are children of a dynamic segment nested inside route groups, returning instant 404 for the entire session. The issue is probabilistic, occurs under module graph load, and is repaired by any file event under app/. Production builds are unaffected.
In Next.js 16.3.6 on Vercel, background cache regeneration started during streaming is not tracked by waitUntil, causing it to be aborted when the serverless function exits, resulting in failed revalidations.