Next.js 15.4.3 introduces subtle refinements compared to its predecessor, version 15.4.2. While the core framework remains consistent, certain internal dependencies and optional functionalities experience updates. A primary distinction lies within the @next/swc packages, representing platform-specific binaries of the SWC compiler, essential for fast builds. Version 15.4.3 updates these binaries across various operating systems, including Darwin (x64 and ARM64), Linux (x64 GNU and MUSL, ARM64 GNU and MUSL) and Windows (x64 and ARM64 MSVC). This suggests potential performance tweaks or bug fixes within the compiler itself.
Furthermore, while most dependencies remain at the same version, minor adjustments in file count and unpacked size between the two versions indicate likely internal modifications, potentially small bug fixes or the optimization of existing features, not reflected in the manifest.
For developers considering the upgrade, assessing the value is based on the specific needs of their projects. If facing obscure compilation issues, platform-specific challenges, or benefiting from bleeding edge optimizations of the SWC compiler (which is very fast), upgrading to 15.4.3 might prove worthwhile. If the project runs well on 15.4.2, assessing if these benefits justify the upgrade is the sensible thing to do. Always test thoroughly for unforeseen degradations.
All the vulnerabilities related to the version 15.4.3 of the package
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
