Next.js 13.0.0 introduces several notable changes compared to version 12.3.7, impacting developers seeking updated features and performance enhancements. One significant shift is the upgraded peer dependency requirement for React from versions 17 or 18 to specifically version 18, potentially mandating updates for projects using older React versions. Also React-dom requirement has changed also to the 18 version.
The core @next/swc compiler, crucial for build and compilation speed, sees a version bump from 12.3.7 to 13.0.0, hinting at potential performance improvements and new language feature support. This is reflected in the platform-specific @next/swc-* packages with similar version jumps. Next.js 13 comes with support for the app/ directory wich provides improvements on the way frontend websites are structured.
Furthermore, the @napi-rs/cli dev dependency updates from 2.7.0 to 2.12.0. It is important to notice that the node-sass and fibers peer dependencies are not present in the newer version. Additionally, there's a change in the versions of several dev dependencies, including a major version bump for web-vitals from 2.x to 3.x. Next 13 is faster than the version 12 because of the implementation of Turbopack. This new architecture gives a new level of speed and improvements. The files added in the newer version are more than 1000 in relation to the previous version.
All the vulnerabilities related to the version 13.0.0 of the package
Next.js missing cache-control header may lead to CDN caching empty reply
Next.js before 13.4.20-canary.13 lacks a cache-control header and thus empty prefetch responses may sometimes be cached by a CDN, causing a denial of service to all users requesting the same URL via that CDN. Cloudflare considers these requests cacheable assets.
Next.js Allows a Denial of Service (DoS) with Server Actions
A Denial of Service (DoS) attack allows attackers to construct requests that leaves requests to Server Actions hanging until the hosting provider cancels the function execution.
Note: Next.js server is idle during that time and only keeps the connection open. CPU and memory footprint are low during that time.
Deployments without any protection against long running Server Action invocations are especially vulnerable. Hosting providers like Vercel or Netlify set a default maximum duration on function execution to reduce the risk of excessive billing.
This is the same issue as if the incoming HTTP request has an invalid Content-Length header or never closes. If the host has no other mitigations to those then this vulnerability is novel.
This vulnerability affects only Next.js deployments using Server Actions.
This vulnerability was resolved in Next.js 14.2.21, 15.1.2, and 13.5.8. We recommend that users upgrade to a safe version.
There are no official workarounds for this vulnerability.
Thanks to the PackDraw team for responsibly disclosing this vulnerability.
Authorization Bypass in Next.js Middleware
It is possible to bypass authorization checks within a Next.js application, if the authorization check occurs in middleware.
15.2.314.2.2513.5.912.3.5Note: Next.js deployments hosted on Vercel are automatically protected against this vulnerability.
If patching to a safe version is infeasible, it is recommend that you prevent external user requests which contain the x-middleware-subrequest header from reaching your Next.js application.
Denial of Service condition in Next.js image optimization
The image optimization feature of Next.js contained a vulnerability which allowed for a potential Denial of Service (DoS) condition which could lead to excessive CPU consumption.
Not affected:
next.config.js file is configured with images.unoptimized set to true or images.loader set to a non-default value.This issue was fully patched in Next.js 14.2.7. We recommend that users upgrade to at least this version.
Ensure that the next.config.js file has either images.unoptimized, images.loader or images.loaderFile assigned.
Brandon Dahler (brandondahler), AWS Dimitrios Vlastaras
Next.js authorization bypass vulnerability
If a Next.js application is performing authorization in middleware based on pathname, it was possible for this authorization to be bypassed.
This issue was patched in Next.js 14.2.15 and later.
If your Next.js application is hosted on Vercel, this vulnerability has been automatically mitigated, regardless of Next.js version.
There are no official workarounds for this vulnerability.
We'd like to thank tyage (GMO CyberSecurity by IERAE) for responsible disclosure of this issue.
Next.js Race Condition to Cache Poisoning
Summary
We received a responsible disclosure from Allam Rachid (zhero) for a low-severity race-condition vulnerability in Next.js. This issue only affects the Pages Router under certain misconfigurations, causing normal endpoints to serve pageProps data instead of standard HTML.
Credit
Thank you to Allam Rachid (zhero) for the responsible disclosure. This research was rewarded as part of our bug bounty program.
Information exposure in Next.js dev server due to lack of origin verification
A low-severity vulnerability in Next.js has been fixed in version 15.2.2. This issue may have allowed limited source code exposure when the dev server was running with the App Router enabled. The vulnerability only affects local development environments and requires the user to visit a malicious webpage while npm run dev is active.
Because the mitigation is potentially a breaking change for some development setups, to opt-in to the fix, you must configure allowedDevOrigins in your next config after upgrading to a patched version. Learn more.
Learn more: https://vercel.com/changelog/cve-2025-48068
Thanks to sapphi-red and Radman Siddiki for responsibly disclosing this issue.
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 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
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
PostCSS line return parsing error
An issue was discovered in PostCSS before 8.4.31. It affects linters using PostCSS to parse external Cascading Style Sheets (CSS). There may be \r discrepancies, as demonstrated by @font-face{ font:(\r/*);} in a rule.
This vulnerability affects linters using PostCSS to parse external untrusted CSS. An attacker can prepare CSS in such a way that it will contains parts parsed by PostCSS as a CSS comment. After processing by PostCSS, it will be included in the PostCSS output in CSS nodes (rules, properties) despite being originally included in a comment.