Security for apps built with v0: what to check
v0 generates Next.js interfaces and apps ready to deploy. The code is clean and modern, but a Next.js app’s security rests on details the AI can’t know about your context: who may call which action, and which variables are sent to the browser.
A concrete example: in 2025, a Next.js flaw (CVE-2025-29927) made it possible to bypass the middleware entirely, which is often used to protect private pages. An app left on a vulnerable version stays exposed.
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Analyse my app for freeThe most common flaws
Secrets in NEXT_PUBLIC_ variables
Any variable prefixed with NEXT_PUBLIC_ is copied into the public JavaScript. An API key placed there is visible to everyone.
Server actions without a session check
A Server Action is a public endpoint. If it doesn’t check who is calling, anyone can modify or delete data.
Vulnerable Next.js version
Flaws in the framework itself, like the middleware bypass, affect every app that isn’t updated.
Injected HTML and open redirects
dangerouslySetInnerHTML fed with external data, or a redirect built from the URL: two classic doors to session theft and phishing.
What Citadel checks (18 live checks)
Code, dependency and secret analysis against OWASP and CWE. Every flaw comes with a plain explanation and the fix prompt to paste into your assistant.
- Next.js version vulnerable to middleware bypass (CVE-2025-29927) A06 · CVE
- Secret exposed in a NEXT_PUBLIC_ variable CWE-200 · A02
- dangerouslySetInnerHTML fed with external data CWE-79 · A03
- Redirect built from URL parameters CWE-601 · A01
- images.remotePatterns open to every domain CWE-918 · A10
- Source maps published in production CWE-540 · A05
- Secrets in the code and config files (100+ key types) CWE-798 · A07
- npm and Composer dependencies with published CVEs or GHSA advisories A06 · CVSS
- Passwords hashed with MD5, SHA-1 or unsalted CWE-916 · A02
- http:// redirects to https:// CWE-319 · A02
- HSTS present with a sufficient duration CWE-319 · A05
- CSP present, without unsafe-inline or unsafe-eval CWE-693 · A05
- Protection against embedding in another page (clickjacking) CWE-1021 · A05
- Secure, HttpOnly and SameSite cookies CWE-614 · CWE-1004
- CORS open to every site with cookies CWE-942 · A05
- nosniff and Referrer-Policy headers, server version hidden CWE-693 · CWE-200
- Forms sent in clear text, or password passed in the URL CWE-319 · CWE-598
- Forms without an anti-CSRF token, or sent to another domain CWE-352 · CWE-201
Frequently asked questions
How do I check the security of a v0 project?
Push the project to GitHub from v0, connect the repository to Citadel, and turn on analysis on every push to be warned as soon as a change introduces a flaw.
Is my code kept?
No. It is analysed in an isolated container with no internet access, then deleted as soon as the analysis ends. Only the results are kept, with secrets masked.
How much does it cost?
The Free plan includes ten analyses a month, no card needed. Paid plans add Citadel AI, analysis on every push and team work.
Other guides
Vibe coding security: the checklist before you put your app online