Skip to content

Next.js patches two unauthenticated RCEs, upgrade to 16.4.1

The out-of-band release Vercel pre-announced on 8 October has landed with two Critical remote code execution fixes and one High-severity denial of service fix.

Source: Next.js

Vercel has published the out-of-band Next.js security release it flagged a week ago, fixing three vulnerabilities in versions 15.0.0 to 15.5.27 and 16.0.0 to 16.4.0. The fixes are in 15.5.28 and 16.4.1.

The first, CVE-2026-96889, is an unauthenticated remote code execution bug in the Image Optimization API when it processes SVG files, caused by a memory flaw in the upstream library Next.js reaches through sharp on glibc-based Linux. The second, not yet assigned a CVE, is also an unauthenticated RCE: any app on 16.0.0 to 16.4.0 with a use cache function that returns more than one typed array is exposed, with no workaround beyond upgrading. A third, High-severity fix closes a denial of service bug in App Router apps that use Server Actions.

npm install next@16.4.1

Why it matters: two unauthenticated RCEs in a framework this widely deployed is as serious as this beat gets. If you’re running Image Optimization or use cache in production, upgrade now rather than waiting for a quiet moment.

The caveat: the use cache bug has no CVE yet, so vulnerability scanners keyed on CVE IDs won’t catch it until one is assigned.

Share

Related reading

ML for Web Devs

Machine learning for web developers: the only mental model you need

You do not need calculus to work with models. You need one idea, that a model is a function you fit instead of write, and the rest follows from things you already know.

Web

View transitions without a framework

Animating between two states used to mean keeping both in the DOM and choreographing them by hand. The browser will now do the hard part for you, in about six lines.

ML for Web Devs

Running a model in the browser, and when that is a good idea

Transformers.js and WebGPU put real models on the client. The demo is easy; knowing which features belong there is the part worth thinking about.

More from The Wire

All briefs

GitHub Copilot retires six AI models today

Gemini 3.7 Flash, GPT-5.5, GPT-5.4, GPT-5.4 mini, GPT-5 mini and Grok 4.5 stop working across Copilot Chat, inline edits, agent mode and completions from today.

via GitHub