NodeJS/next/15.4.0-canary.52

Next.js: Unbounded next/image disk cache growth can exhaust storage

Summary

The default Next.js image optimization disk cache (/_next/image) did not have a configurable upper bound, allowing unbounded cache growth.

Impact

An attacker could generate many unique image-optimization variants and exhaust disk space, causing denial of service. Note that this does not impact platforms that have their own image optimization capabilities, such as Vercel.

Patches

Fixed by adding an LRU-backed disk cache with images.maximumDiskCacheSize, including eviction of least-recently-used entries when the limit is exceeded. Setting maximumDiskCacheSize: 0 disables disk caching.

Workarounds

If upgrade is not immediately possible: - Periodically clean .next/cache/images. - Reduce variant cardinality (e.g., tighten values for images.localPatterns, images.remotePatterns, and images.qualities)

Next.js Improper Middleware Redirect Handling Leads to SSRF

A vulnerability in Next.js Middleware has been fixed in v14.2.32 and v15.4.7. The issue occurred when request headers were directly passed into NextResponse.next(). In self-hosted applications, this could allow Server-Side Request Forgery (SSRF) if certain sensitive headers from the incoming request were reflected back into the response.

All users implementing custom middleware logic in self-hosted environments are strongly encouraged to upgrade and verify correct usage of the next() function.

More details at Vercel Changelog

Next.js has Unbounded Memory Consumption via PPR Resume Endpoint

A denial of service vulnerability exists in Next.js versions with Partial Prerendering (PPR) enabled when running in minimal mode. The PPR resume endpoint accepts unauthenticated POST requests with the Next-Resume: 1 header and processes attacker-controlled postponed state data. Two closely related vulnerabilities allow an attacker to crash the server process through memory exhaustion:

1. Unbounded request body buffering: The server buffers the entire POST request body into memory using Buffer.concat() without enforcing any size limit, allowing arbitrarily large payloads to exhaust available memory.

2. Unbounded decompression (zipbomb): The resume data cache is decompressed using inflateSync() without limiting the decompressed output size. A small compressed payload can expand to hundreds of megabytes or gigabytes, causing memory exhaustion.

Both attack vectors result in a fatal V8 out-of-memory error (FATAL ERROR: Reached heap limit Allocation failed - JavaScript heap out of memory) causing the Node.js process to terminate. The zipbomb variant is particularly dangerous as it can bypass reverse proxy request size limits while still causing large memory allocation on the server.

To be affected, an application must run with experimental.ppr: true or cacheComponents: true configured along with the NEXTPRIVATEMINIMAL_MODE=1 environment variable.

Strongly consider upgrading to 15.6.0-canary.61 or 16.1.5 to reduce risk and prevent availability issues in Next applications.

Next.js self-hosted applications vulnerable to DoS via Image Optimizer remotePatterns configuration

A DoS vulnerability exists in self-hosted Next.js applications that have remotePatterns configured for the Image Optimizer. The image optimization endpoint (/_next/image) loads external images entirely into memory without enforcing a maximum size limit, allowing an attacker to cause out-of-memory conditions by requesting optimization of arbitrarily large images. This vulnerability requires that remotePatterns is configured to allow image optimization from external domains and that the attacker can serve or control a large image on an allowed domain.

Strongly consider upgrading to 15.5.10 and 16.1.5 to reduce risk and prevent availability issues in Next applications.

Next.js is vulnerable to RCE in React flight protocol

A vulnerability affects certain React packages¹ for versions 19.0.0, 19.1.0, 19.1.1, and 19.2.0 and frameworks that use the affected packages, including Next.js 15.x and 16.x using the App Router. The issue is tracked upstream as CVE-2025-55182.

Fixed in: React: 19.0.1, 19.1.2, 19.2.1 Next.js: 15.0.5, 15.1.9, 15.2.6, 15.3.6, 15.4.8, 15.5.7, 16.0.7, 15.6.0-canary.58, 16.1.0-canary.12+

The vulnerability also affects experimental canary releases starting with 14.3.0-canary.77. Users on any of the 14.3 canary builds should either downgrade to a 14.x stable release or 14.3.0-canary.76.

All users of stable 15.x or 16.x Next.js versions should upgrade to a patched, stable version immediately.

¹ The affected React packages are: - react-server-dom-parcel - react-server-dom-turbopack - react-server-dom-webpack

Next.js Affected by Cache Key Confusion for Image Optimization API Routes

A vulnerability in Next.js Image Optimization has been fixed in v15.4.5 and v14.2.31. When images returned from API routes vary based on request headers (such as Cookie or Authorization), these responses could be incorrectly cached and served to unauthorized users due to a cache key confusion bug.

All users are encouraged to upgrade if they use API routes to serve images that depend on request headers and have image optimization enabled.

More details at Vercel Changelog

Next.js: HTTP request smuggling in rewrites

Summary

When Next.js rewrites proxy traffic to an external backend, a crafted DELETE/OPTIONS request using Transfer-Encoding: chunked could trigger request boundary disagreement between the proxy and backend. This could allow request smuggling through rewritten routes.

Impact

An attacker could smuggle a second request to unintended backend routes (for example, internal/admin endpoints), bypassing assumptions that only the configured rewrite destination/path is reachable. This does not impact applications hosted on providers that handle rewrites at the CDN level, such as Vercel.

Patches

The vulnerability originated in an upstream library vendored by Next.js. It is fixed by updating that dependency’s behavior so content-length: 0 is added only when both content-length and transfer-encoding are absent, and transfer-encoding is no longer removed in that code path.

Workarounds

If upgrade is not immediately possible: - Block chunked DELETE/OPTIONS requests on rewritten routes at your edge/proxy. - Enforce authentication/authorization on backend routes per our security guidance.

Next.js HTTP request deserialization can lead to DoS when using insecure React Server Components

A vulnerability affects certain React Server Components packages for versions 19.0.x, 19.1.x, and 19.2.x and frameworks that use the affected packages, including Next.js 13.x, 14.x, 15.x, and 16.x using the App Router. The issue is tracked upstream as CVE-2026-23864.

A specially crafted HTTP request can be sent to any App Router Server Function endpoint that, when deserialized, may trigger excessive CPU usage, out-of-memory exceptions, or server crashes. This can result in denial of service in unpatched environments.

Next Vulnerable to Denial of Service with Server Components

A vulnerability affects certain React packages for versions 19.0.0, 19.0.1, 19.1.0, 19.1.1, 19.1.2, 19.2.0, and 19.2.1 and frameworks that use the affected packages, including Next.js 15.x and 16.x using the App Router. The issue is tracked upstream as CVE-2025-55184.

A malicious HTTP request can be crafted and sent to any App Router endpoint that, when deserialized, can cause the server process to hang and consume CPU. This can result in denial of service in unpatched environments.

Next Server Actions Source Code Exposure

A vulnerability affects certain React packages for versions 19.0.0, 19.0.1, 19.1.0, 19.1.1, 19.1.2, 19.2.0, and 19.2.1 and frameworks that use the affected packages, including Next.js 15.x and 16.x using the App Router. The issue is tracked upstream as CVE-2025-55183.

A malicious HTTP request can be crafted and sent to any App Router endpoint that can return the compiled source code of Server Functions. This could reveal business logic, but would not expose secrets unless they were hardcoded directly into Server Function code.

Next.js Content Injection Vulnerability for Image Optimization

A vulnerability in Next.js Image Optimization has been fixed in v15.4.5 and v14.2.31. The issue allowed attacker-controlled external image sources to trigger file downloads with arbitrary content and filenames under specific configurations. This behavior could be abused for phishing or malicious file delivery.

All users relying on images.domains or images.remotePatterns are encouraged to upgrade and verify that external image sources are strictly validated.

More details at Vercel Changelog