Summary
Nuxt dev server exposes generated appSecret through Vite file serving
Workarounds
Set NUXT_APP_SECRET in .env to a random value of at least 32 characters (for example the output of openssl rand -base64 32), or avoid exposing the dev server to untrusted networks.
If a dev server using a generated secret has been reachable by untrusted clients, delete .nuxt/app-secret (a new secret is generated on the next nuxt dev) or set NUXT_APP_SECRET. Either invalidates existing dev sessions.
Impact
When no appSecret is configured (via NUXT_APP_SECRET, NITRO_APP_SECRET or runtimeConfig.appSecret), nuxt dev generates a development secret and stores it in <buildDir>/app-secret (by default .nuxt/app-secret). The build directory is inside the directories that Nuxt passes to Vite's server.fs.allow, so the file can be fetched from the dev server:
curl http://<dev-server>/_nuxt/@fs/<absolute-path-to-project>/.nuxt/app-secret
Anyone who can read it can compute every secret derived from it with deriveSecret(), including the default password used by useSession, and so can forge session cookies accepted by that dev server.
Exploitation requires direct HTTP access to the dev server. nuxt dev listens on localhost by default, so this mainly affects dev servers that are exposed to a network (for example with --host, a published container port or a tunnel). A malicious website cannot read the file through a developer's browser: Vite's CORS and host checks prevent pages on other origins from reading the response.
Production builds never generate an appSecret and are not affected. Dev servers with an explicitly configured appSecret do not use the generated file.
CVE-2026-119201 has a CVSS score of 4.8 (Medium). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (4.6.3); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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Fixed in @nuxt/vite-builder 4.6.3, which nuxt 4.6.3 depends on. The dev server now adds app-secret to Vite's server.fs.deny, keeping Vite's default deny list.
Frequently Asked Questions
- What is CVE-2026-119201? CVE-2026-119201 is a medium-severity security vulnerability in @nuxt/vite-builder (npm), affecting versions >= 4.6.0, < 4.6.3. It is fixed in 4.6.3.
- How severe is CVE-2026-119201? CVE-2026-119201 has a CVSS score of 4.8 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which versions of @nuxt/vite-builder are affected by CVE-2026-119201? @nuxt/vite-builder (npm) versions >= 4.6.0, < 4.6.3 is affected.
- Is there a fix for CVE-2026-119201? Yes. CVE-2026-119201 is fixed in 4.6.3. Upgrade to this version or later.
- Is CVE-2026-119201 exploitable, and should I be worried? Whether CVE-2026-119201 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2026-119201 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2026-119201? Upgrade
@nuxt/vite-builderto 4.6.3 or later.