CVE-2021-37699 Open Redirect in Next.js versions below 11.1.0
Attackers can redirect users to malicious sites via specially encoded paths in statically generated error pages, facilitating phishing attacks.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2021-37699?
CVE-2021-37699 is a medium-severity vulnerability in Vercel Next.js, published on 11 Aug 2021. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official description
Next.js is an open source website development framework to be used with the React library. In affected versions specially encoded paths could be used when pages/_error.js was statically generated allowing an open redirect to occur to an external site. In general, this redirect does not directly harm users although can allow for phishing attacks by redirecting to an attacker's domain from a trusted domain. We recommend everyone to upgrade regardless of whether you can reproduce the issue or not. The issue has been patched in release 11.1.0.
Weakness: CWE-601
Which versions are affected by CVE-2021-37699?
2 open source packages ship an affected version, including next. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
next npm | From 0.9.9 | 11.1.0 |
next npm | From 0.9.9 | 11.1.0 |
Products include Vercel Next.js.
How do I fix CVE-2021-37699?
Upgrade next to 11.1.0 or later.
Is CVE-2021-37699 being exploited?
There is no known exploitation of CVE-2021-37699 in the wild and no public exploit code.
Other vulnerabilities in Vercel Next.js
- CVE-2025-29927 Authorization Bypass in Next.js Middleware
- CVE-2026-44578 Next.js: Server-side request forgery in applications using WebSocket upgrades
- CVE-2026-94483 Next.js: Server-Side Request Forgery in Image Optimization
- CVE-2026-64642 Next.js: Middleware / Proxy bypass in App Router applications using Turbopack and single locale
- CVE-2026-64645 Next.js: Server-Side Request Forgery in rewrites via attacker-controlled destination hostname
Sources
Also known as GHSA-vxf5-wxwp-m7g9.