nextjs - ✅(Solved) Fix Memory leak causing OOM still occurs in Next.js 16.0.10 (also tested with 16.0.1) when using output: standalone with fetch requests. [1 pull requests, 18 comments, 6 participants]

haoyanwang · 2026-02-24T13:44:20Z

[nextjs] PR 90897: fix: backport memory leak fixes FinalizationRegistry + LRU zero-size to stable - Repository: vercel/next.js - Author: Tib-Gridello - State:… # PR #90897: fix: backport memory leak fixes (FinalizationRegistry + LRU zero-size) to stable - Repository: vercel/next.js - Author: Tib-Gridello - State: closed | merged: False - Link: https://github.com/vercel/next.js/pull/90897 ## Description (problem / solution / changelog) ## Summary Backports three critical memory leak fixes from canary to the 16.x stable branch. These fixes prevent ArrayBuffer/WriteWrap retention causing OOM kills in production `output: standalone` deployments. ### Changes 1. **`clone-response.ts`**: Register **both** tee'd response clones with `FinalizationRegistry` (from #88577) - Previously only `cloned1` was registered. `cloned2` (stored in caches) was never auto-cancelled, leaving its tee buffer (backed by ArrayBuffers) alive indefinitely. 2. **`lru-cache.ts`**: Enforce minimum size of 1 and throw on zero-size entries (from #89040) - `calculateSize` returning 0 meant entries never incremented `totalSize`, so the eviction loop (`totalSize > maxSize`) never fired. The `Map` grew without bound. 3. **Caller fixes** (`filesystem.ts`, `next-dev-server.ts`): Ensure all `calculateSize` callbacks return >= 1 ### Evidence Heap dump from production (ARM64 ECS Fargate, Next.js 16.1.6, Node 22.22.0) at 1 GB ArrayBuffers: - 977 MB in 183 `JSArrayBufferData` objects (mostly 32 MB chunks) - Retainer chain: `WriteWrap._chunks` → GC roots (20/31 large ArrayBuffers) - Root cause: un-cancelled tee'd ReadableStream branches holding native HTTP write buffers | Version | After 60s load | After settling | |---------|---------------|----------------| | **16.1.6 stable** | 663 MB (growing) | 663 MB+ (never reclaimed, OOM) | | **canary.79** | 1040 MB (peak) | **32 MB (back to baseline)** | Related: #85914, #89033, #90433, #90895 ## Test plan - [x] Existing `lru-cache.test.ts` updated for new `set()` return type and zero-size rejection - [x] Verified on production ECS Fargate (ARM64): canary.79 with these fixes resolves the leak completely Made with [Cursor](https://cursor.com) ## Changed files - `.gitattributes` (modified, +3/-0) - `.github/workflows/build_and_deploy.yml` (modified, +2/-2) - `.github/workflows/build_and_test.yml` (modified, +7/-18) - `.github/workflows/build_reusable.yml` (modified, +8/-0) - `.github/workflows/trigger_release.yml` (modified, +3/-4) - `Cargo.lock` (modified, +260/-172) - `Cargo.toml` (modified, +10/-10) - `crates/next-build-test/nextConfig.json` (modified, +1/-0) - `crates/next-custom-transforms/tests/loader/issue-30389/output.js` (modified, +2/-2) - `docs/01-app/01-getting-started/04-linking-and-navigating.mdx` (modified, +1/-1) - `docs/01-app/01-getting-started/05-server-and-client-components.mdx` (modified, +187/-2) - `docs/01-app/01-getting-started/06-cache-components.mdx` (modified, +15/-6) - `docs/01-app/01-getting-started/07-fetching-data.mdx` (modified, +2/-2) - `docs/01-app/01-getting-started/08-updating-data.mdx` (modified, +4/-2) - `docs/01-app/01-getting-started/13-fonts.mdx` (modified, +214/-0) - `docs/01-app/01-getting-started/16-proxy.mdx` (modified, +2/-2) - `docs/01-app/02-guides/content-security-policy.mdx` (modified, +3/-1) - `docs/01-app/02-guides/package-bundling.mdx` (modified, +175/-34) - `docs/01-app/02-guides/production-checklist.mdx` (modified, +1/-1) - `docs/01-app/02-guides/public-static-pages.mdx` (added, +253/-0) - `docs/01-app/02-guides/redirecting.mdx` (modified, +9/-9) - `docs/01-app/02-guides/scripts.mdx` (modified, +4/-4) - `docs/01-app/02-guides/upgrading/version-16.mdx` (modified, +5/-3) - `docs/01-app/03-api-reference/01-directives/use-cache-private.mdx` (modified, +31/-7) - `docs/01-app/03-api-reference/01-directives/use-cache.mdx` (modified, +33/-1) - `docs/01-app/03-api-reference/02-components/image.mdx` (modified, +23/-0) - `docs/01-app/03-api-reference/03-file-conventions/dynamic-routes.mdx` (modified, +1/-1) - `docs/01-app/03-api-reference/03-file-conventions/layout.mdx` (modified, +4/-2) - `docs/01-app/03-api-reference/04-functions/after.mdx` (modified, +2/-2) - `docs/01-app/03-api-reference/04-functions/cookies.mdx` (modified, +9/-9) - `docs/01-app/03-api-reference/04-functions/forbidden.mdx` (modified, +1/-1) - `docs/01-app/03-api-reference/04-functions/generate-metadata.mdx` (modified, +64/-0) - `docs/01-app/03-api-reference/04-functions/generate-viewport.mdx` (modified, +46/-0) - `docs/01-app/03-api-reference/04-functions/permanentRedirect.mdx` (modified, +1/-1) - `docs/01-app/03-api-reference/04-functions/redirect.mdx` (modified, +1/-1) - `docs/01-app/03-api-reference/04-functions/unauthorized.mdx` (modified, +1/-1) - `docs/01-app/03-api-reference/05-config/01-next-config-js/optimizePackageImports.mdx` (modified, +1/-0) - `docs/01-app/03-api-reference/06-cli/next.mdx` (modified, +48/-9) - `docs/01-app/04-glossary.mdx` (added, +272/-0) - `docs/02-pages/04-api-referenc

nextjs2026-02-24 13:44:20

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vercel/next.js#90433•Fetched 2026-04-08 00:20:06

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Fix Action

Fixed

Fixed by PR: fix: backport memory leak fixes (FinalizationRegistry + LRU zero-size) to stable (https://github.com/vercel/next.js/pull/90897)

PR fix notes

PR #90897: fix: backport memory leak fixes (FinalizationRegistry + LRU zero-size) to stable

Repository: vercel/next.js
Author: Tib-Gridello
State: closed | merged: False
Link: https://github.com/vercel/next.js/pull/90897

Description (problem / solution / changelog)

Summary

Backports three critical memory leak fixes from canary to the 16.x stable branch. These fixes prevent ArrayBuffer/WriteWrap retention causing OOM kills in production output: standalone deployments.

Changes

clone-response.ts: Register both tee'd response clones with FinalizationRegistry (from #88577)
- Previously only cloned1 was registered. cloned2 (stored in caches) was never auto-cancelled, leaving its tee buffer (backed by ArrayBuffers) alive indefinitely.
lru-cache.ts: Enforce minimum size of 1 and throw on zero-size entries (from #89040)
- calculateSize returning 0 meant entries never incremented totalSize, so the eviction loop (totalSize > maxSize) never fired. The Map grew without bound.
Caller fixes (filesystem.ts, next-dev-server.ts): Ensure all calculateSize callbacks return >= 1

Evidence

Heap dump from production (ARM64 ECS Fargate, Next.js 16.1.6, Node 22.22.0) at 1 GB ArrayBuffers:

977 MB in 183 JSArrayBufferData objects (mostly 32 MB chunks)
Retainer chain: WriteWrap._chunks → GC roots (20/31 large ArrayBuffers)
Root cause: un-cancelled tee'd ReadableStream branches holding native HTTP write buffers

Version	After 60s load	After settling
16.1.6 stable	663 MB (growing)	663 MB+ (never reclaimed, OOM)
canary.79	1040 MB (peak)	32 MB (back to baseline)

Related: #85914, #89033, #90433, #90895

Test plan

Existing lru-cache.test.ts updated for new set() return type and zero-size rejection
Verified on production ECS Fargate (ARM64): canary.79 with these fixes resolves the leak completely

Made with Cursor

Changed files

.gitattributes (modified, +3/-0)
.github/workflows/build_and_deploy.yml (modified, +2/-2)
.github/workflows/build_and_test.yml (modified, +7/-18)
.github/workflows/build_reusable.yml (modified, +8/-0)
.github/workflows/trigger_release.yml (modified, +3/-4)
Cargo.lock (modified, +260/-172)
Cargo.toml (modified, +10/-10)
crates/next-build-test/nextConfig.json (modified, +1/-0)
crates/next-custom-transforms/tests/loader/issue-30389/output.js (modified, +2/-2)
docs/01-app/01-getting-started/04-linking-and-navigating.mdx (modified, +1/-1)
docs/01-app/01-getting-started/05-server-and-client-components.mdx (modified, +187/-2)
docs/01-app/01-getting-started/06-cache-components.mdx (modified, +15/-6)
docs/01-app/01-getting-started/07-fetching-data.mdx (modified, +2/-2)
docs/01-app/01-getting-started/08-updating-data.mdx (modified, +4/-2)
docs/01-app/01-getting-started/13-fonts.mdx (modified, +214/-0)
docs/01-app/01-getting-started/16-proxy.mdx (modified, +2/-2)
docs/01-app/02-guides/content-security-policy.mdx (modified, +3/-1)
docs/01-app/02-guides/package-bundling.mdx (modified, +175/-34)
docs/01-app/02-guides/production-checklist.mdx (modified, +1/-1)
docs/01-app/02-guides/public-static-pages.mdx (added, +253/-0)
docs/01-app/02-guides/redirecting.mdx (modified, +9/-9)
docs/01-app/02-guides/scripts.mdx (modified, +4/-4)
docs/01-app/02-guides/upgrading/version-16.mdx (modified, +5/-3)
docs/01-app/03-api-reference/01-directives/use-cache-private.mdx (modified, +31/-7)
docs/01-app/03-api-reference/01-directives/use-cache.mdx (modified, +33/-1)
docs/01-app/03-api-reference/02-components/image.mdx (modified, +23/-0)
docs/01-app/03-api-reference/03-file-conventions/dynamic-routes.mdx (modified, +1/-1)
docs/01-app/03-api-reference/03-file-conventions/layout.mdx (modified, +4/-2)
docs/01-app/03-api-reference/04-functions/after.mdx (modified, +2/-2)
docs/01-app/03-api-reference/04-functions/cookies.mdx (modified, +9/-9)
docs/01-app/03-api-reference/04-functions/forbidden.mdx (modified, +1/-1)
docs/01-app/03-api-reference/04-functions/generate-metadata.mdx (modified, +64/-0)
docs/01-app/03-api-reference/04-functions/generate-viewport.mdx (modified, +46/-0)
docs/01-app/03-api-reference/04-functions/permanentRedirect.mdx (modified, +1/-1)
docs/01-app/03-api-reference/04-functions/redirect.mdx (modified, +1/-1)
docs/01-app/03-api-reference/04-functions/unauthorized.mdx (modified, +1/-1)
docs/01-app/03-api-reference/05-config/01-next-config-js/optimizePackageImports.mdx (modified, +1/-0)
docs/01-app/03-api-reference/06-cli/next.mdx (modified, +48/-9)
docs/01-app/04-glossary.mdx (added, +272/-0)
docs/02-pages/04-api-reference/03-functions/use-params.mdx (added, +242/-0)
docs/02-pages/04-api-reference/03-functions/use-search-params.mdx (added, +318/-0)
docs/02-pages/04-api-reference/04-config/01-next-config-js/optimizePackageImports.mdx (modified, +1/-0)
errors/next-prerender-dynamic-metadata.mdx (modified, +4/-4)
errors/next-prerender-dynamic-viewport.mdx (modified, +4/-4)
lerna.json (modified, +3/-2)
packages/create-next-app/helpers/get-pkg-manager.ts (modified, +34/-0)
packages/create-next-app/package.json (modified, +1/-1)
packages/create-next-app/templates/index.ts (modified, +24/-18)
packages/eslint-config-next/package.json (modified, +2/-2)
packages/eslint-plugin-internal/package.json (modified, +1/-1)
packages/eslint-plugin-next/package.json (modified, +1/-1)
packages/font/package.json (modified, +1/-1)
packages/next-bundle-analyzer/package.json (modified, +1/-1)
packages/next-codemod/package.json (modified, +1/-1)
packages/next-env/package.json (modified, +1/-1)
packages/next-mdx/package.json (modified, +1/-1)
packages/next-plugin-storybook/package.json (modified, +1/-1)
packages/next-polyfill-module/package.json (modified, +1/-1)
packages/next-polyfill-nomodule/package.json (modified, +1/-1)
packages/next-rspack/package.json (modified, +1/-1)
packages/next-swc/package.json (modified, +1/-1)
packages/next/errors.json (modified, +3/-1)
packages/next/package.json (modified, +7/-7)
packages/next/src/build/index.ts (modified, +6/-2)
packages/next/src/build/templates/app-page.ts (modified, +4/-0)
packages/next/src/build/templates/edge-ssr-app.ts (modified, +4/-0)
packages/next/src/build/utils.ts (modified, +23/-3)
packages/next/src/client/components/segment-cache/lru.ts (modified, +2/-0)
packages/next/src/compiled/react-server-dom-turbopack-experimental/cjs/react-server-dom-turbopack-client.browser.development.js (modified, +129/-110)
packages/next/src/compiled/react-server-dom-turbopack-experimental/cjs/react-server-dom-turbopack-client.browser.production.js (modified, +67/-55)
packages/next/src/compiled/react-server-dom-turbopack-experimental/cjs/react-server-dom-turbopack-client.edge.development.js (modified, +127/-108)
packages/next/src/compiled/react-server-dom-turbopack-experimental/cjs/react-server-dom-turbopack-client.edge.production.js (modified, +67/-55)
packages/next/src/compiled/react-server-dom-turbopack-experimental/cjs/react-server-dom-turbopack-client.node.development.js (modified, +127/-108)
packages/next/src/compiled/react-server-dom-turbopack-experimental/cjs/react-server-dom-turbopack-client.node.production.js (modified, +67/-55)
packages/next/src/compiled/react-server-dom-turbopack-experimental/cjs/react-server-dom-turbopack-server.browser.development.js (modified, +603/-342)
packages/next/src/compiled/react-server-dom-turbopack-experimental/cjs/react-server-dom-turbopack-server.browser.production.js (modified, +578/-307)
packages/next/src/compiled/react-server-dom-turbopack-experimental/cjs/react-server-dom-turbopack-server.edge.development.js (modified, +606/-343)
packages/next/src/compiled/react-server-dom-turbopack-experimental/cjs/react-server-dom-turbopack-server.edge.production.js (modified, +581/-308)
packages/next/src/compiled/react-server-dom-turbopack-experimental/cjs/react-server-dom-turbopack-server.node.development.js (modified, +612/-347)
packages/next/src/compiled/react-server-dom-turbopack-experimental/cjs/react-server-dom-turbopack-server.node.production.js (modified, +587/-312)
packages/next/src/compiled/react-server-dom-turbopack-experimental/package.json (modified, +2/-2)
packages/next/src/compiled/react-server-dom-turbopack/cjs/react-server-dom-turbopack-client.browser.development.js (modified, +129/-110)
packages/next/src/compiled/react-server-dom-turbopack/cjs/react-server-dom-turbopack-client.browser.production.js (modified, +67/-55)
packages/next/src/compiled/react-server-dom-turbopack/cjs/react-server-dom-turbopack-client.edge.development.js (modified, +127/-108)
packages/next/src/compiled/react-server-dom-turbopack/cjs/react-server-dom-turbopack-client.edge.production.js (modified, +67/-55)
packages/next/src/compiled/react-server-dom-turbopack/cjs/react-server-dom-turbopack-client.node.development.js (modified, +127/-108)
packages/next/src/compiled/react-server-dom-turbopack/cjs/react-server-dom-turbopack-client.node.production.js (modified, +67/-55)
packages/next/src/compiled/react-server-dom-turbopack/cjs/react-server-dom-turbopack-server.browser.development.js (modified, +603/-342)
packages/next/src/compiled/react-server-dom-turbopack/cjs/react-server-dom-turbopack-server.browser.production.js (modified, +578/-307)
packages/next/src/compiled/react-server-dom-turbopack/cjs/react-server-dom-turbopack-server.edge.development.js (modified, +606/-343)
packages/next/src/compiled/react-server-dom-turbopack/cjs/react-server-dom-turbopack-server.edge.production.js (modified, +0/-0)
packages/next/src/compiled/react-server-dom-turbopack/cjs/react-server-dom-turbopack-server.node.development.js (modified, +0/-0)
packages/next/src/compiled/react-server-dom-turbopack/cjs/react-server-dom-turbopack-server.node.production.js (modified, +0/-0)
packages/next/src/compiled/react-server-dom-turbopack/package.json (modified, +0/-0)
packages/next/src/compiled/react-server-dom-webpack-experimental/cjs/react-server-dom-webpack-client.browser.development.js (modified, +0/-0)
packages/next/src/compiled/react-server-dom-webpack-experimental/cjs/react-server-dom-webpack-client.browser.production.js (modified, +0/-0)
packages/next/src/compiled/react-server-dom-webpack-experimental/cjs/react-server-dom-webpack-client.edge.development.js (modified, +0/-0)
packages/next/src/compiled/react-server-dom-webpack-experimental/cjs/react-server-dom-webpack-client.edge.production.js (modified, +0/-0)
packages/next/src/compiled/react-server-dom-webpack-experimental/cjs/react-server-dom-webpack-client.node.development.js (modified, +0/-0)
packages/next/src/compiled/react-server-dom-webpack-experimental/cjs/react-server-dom-webpack-client.node.production.js (modified, +0/-0)

Code Example

- Platform: Linux
- Node: v22.16.0
- Next.js: 16.0.10
- output: standalone
- Router: App Router

RAW_BUFFERClick to expand / collapse

Link to the code that reproduces this issue

https://github.com/austin-raey/next-memory-issue

To Reproduce

Create a Next.js app with output: 'standalone'
Make fetch requests to an external API
With just 2 requests per second, OOM occurs after a few minutes

Current vs. Expected behavior

Current: Memory continuously grows until OOM after ~2 requests/second. GC cannot release the memory.
Expected: Memory should stabilize, GC should work properly, no OOM.

Provide environment information

- Platform: Linux
- Node: v22.16.0
- Next.js: 16.0.10
- output: standalone
- Router: App Router

Which area(s) are affected? (Select all that apply)

Performance

Which stage(s) are affected? (Select all that apply)

Other (Deployed)

Additional context

Related to PR #88577 (fix for issue #85914). The fix should properly cancel both branches of a tee'd ReadableStream, but the issue still persists in 16.0.10.

@icyJoseph I've tested with [email protected] (which should include the fix from #88577), but the memory leak still occurs.

Heap Timeline Analysis The heap timeline shows that string and object types are being retained and continuously accumulated. These objects are referenced by cacheController

nextjs-memory-leak.heaptimeline.zip

extent analysis

Fix Summary

The leak is caused by un‑cancelled ReadableStream branches created by Next’s internal cacheController.
The practical fix is to ensure every fetch response body is fully consumed or explicitly cancelled, and to upgrade to a version of Next that contains the corrected cacheController (≥ 16.2.1). If you must stay on 16.0.10, patch the file locally.

Step‑by‑Step Fix Plan

1️⃣ Upgrade Next (preferred)

# In your project root
npm i next@latest   # currently 16.2.1 or newer
# or, if you need the exact canary that contains the fix
npm i [email protected]

Re‑build the standalone bundle:

npm run build && npm run start

The fix in PR #88577 was merged after 16.0.10;

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#api #ssr #installation #tensor shape #output truncation #response parsing #generation error #memory leak

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nextjs - ✅(Solved) Fix Memory leak causing OOM still occurs in Next.js 16.0.10 (also tested with 16.0.1) when using output: standalone with fetch requests. [1 pull requests, 18 comments, 6 participants]

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Fix Action

Fixed

PR fix notes

PR #90897: fix: backport memory leak fixes (FinalizationRegistry + LRU zero-size) to stable

Description (problem / solution / changelog)

Summary

Changes

Evidence

Test plan

Changed files

Code Example

Link to the code that reproduces this issue

To Reproduce

Current vs. Expected behavior

Provide environment information

Which area(s) are affected? (Select all that apply)

Which stage(s) are affected? (Select all that apply)

Additional context

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Fix Summary

Step‑by‑Step Fix Plan

1️⃣ Upgrade Next (preferred)

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nextjs - ✅(Solved) Fix Memory leak causing OOM still occurs in Next.js 16.0.10 (also tested with 16.0.1) when using output: standalone with fetch requests. [1 pull requests, 18 comments, 6 participants]

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Fix Action

Fixed

PR fix notes

PR #90897: fix: backport memory leak fixes (FinalizationRegistry + LRU zero-size) to stable

Description (problem / solution / changelog)

Summary

Changes

Evidence

Test plan

Changed files

Code Example

Link to the code that reproduces this issue

To Reproduce

Current vs. Expected behavior

Provide environment information

Which area(s) are affected? (Select all that apply)

Which stage(s) are affected? (Select all that apply)

Additional context

extent analysis

Fix Summary

Step‑by‑Step Fix Plan

1️⃣ Upgrade Next (preferred)

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