Next.js 15.1.2 is a minor version update focusing on refinements and bug fixes following the 15.1.1 release, rather than introducing groundbreaking new features. Examining the package manifests reveals subtle modifications primarily within the optional dependencies and internal packages. Specifically, the @next/swc-* packages (platform-specific builds of the SWC compiler) have been bumped from version 15.1.1 to 15.1.2, indicating updates or patches within the SWC compilation pipeline. This is crucial for developers, as SWC is a core component for fast builds and refreshes.
Furthermore, @next/polyfill-module and @next/polyfill-nomodule are also update into 15.1.2 from the previous version. Also, @next/react-refresh-utils is bumped to version 15.1.2 from 15.1.1. Aside from those packages, other internal packages like @next/env and @next/font share the same modification.
While the dependency lists in dependencies and devDependencies appear largely identical, developers should note potential indirect dependency updates stemming from these core package upgrades. The dist object showcases a minor increase in unpackedSize from 120566250 to 120581261, alongside a later release date. This suggests the inclusion of additional code or assets, possibly related to the SWC or polyfill updates and bug fixes. This version ensures compatibility, performance optimisation, and stability improvements, solidifying its significance for developers relying on the Next.js framework. Before upgrading, it is a good practice to review the detailed changelog for a comprehensive understanding of specific changes, bug resolutions, and potential breaking changes affecting their particular application setup.
All the vulnerabilities related to the version 15.1.2 of the package
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.
Next.JS vulnerability can lead to DoS via cache poisoning
A vulnerability affecting Next.js has been addressed. It impacted versions 15.0.4 through 15.1.8 and involved a cache poisoning bug leading to a Denial of Service (DoS) condition.
Under certain conditions, this issue may allow a HTTP 204 response to be cached for static pages, leading to the 204 response being served to all users attempting to access the page
More details: CVE-2025-49826
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.
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.
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