MediumCVE-2026-119201

Nuxt dev server exposes generated appSecret through Vite file serving (CVE-2026-119201)

Published 29.10.2026Last modified 30.10.2026Sources: OSV, Hersteller, CVE.org

What is affected, what to do

Update @nuxt/vite-builder to version 4.6.3.

Affected: Nuxt gte 4.6.0, < 4.6.3..*

Not sure whether and how you are affected? Ask a question about this vulnerability

Metrics

4.8

Priority

XIEM Effective CVSS: highest available CVSS rating from NVD and vendor data.

Source: Vendor (CNA), CVSS v3

4.8

CVSS v3

Severity Medium on the scale from 0 to 10.

Source: OSV, Hersteller, CVE.org

0.2 %

EPSS score

Low — model estimates < 1% exploitation likelihood.

Source: FIRST EPSS, percentile 10.5

Show all metrics

Severity: Medium
Priority (0–325) The priority score is a consolidated metric that condenses several individual signals into a single, action-guiding ranking: technical severity (CVSS), exploitation likelihood (EPSS), known-exploited status (KEV) and the context of the affected asset. The aim is to answer the only truly important question in vulnerability management: what first? Read in glossary: 54.88 Methodology
Exploit maturity An exploit is code or a technique that specifically uses a concrete vulnerability to force unintended behaviour — such as executing code or escalating privileges. It is the tool that turns a theoretical flaw into a practical attack. Read in glossary: no public PoC known
XIEM Effective CVSS XIEM® is the tiered managed-security operating model from NEOSEC and a registered trademark of NEOSEC GmbH. It extends classic SIEM — the central collection, normalisation and correlation of security-relevant events — with endpoint forensics, network visibility and deception technology, and consolidates them into three building tiers: Sentry, Orchestrate and Command. Read in glossary: 4.8 Methodology
CVSS v3 CVSS is the globally established, open standard for assessing the technical severity of a vulnerability on a scale from 0 to 10. It describes how easily a flaw can be exploited and what damage it can cause — but not how likely its actual exploitation is. CVSS and the complementary EPSS deliberately answer different questions. Read in glossary: 4.8
EPSS score The EPSS score is the absolute model output for an individual vulnerability: the estimated probability of real-world exploitation within the next 30 days, expressed as a value between 0 and 1 (i.e. 0 % to 100 %). A score of 0.42 means „the model estimates a 42 % chance of real-world exploitation within 30 days“. Read in glossary: 0.2 %; Low — model estimates < 1% exploitation likelihood.
EPSS percentile The EPSS percentile is the relative position of a vulnerability within all EPSS-scored CVEs, expressed as a value between 0 and 1. A percentile of 0.90 means „this CVE has a higher EPSS score than 90 % of all other scored CVEs“. Unlike the EPSS score, it is not a probability — but a positioning within a ranking. Read in glossary: 10.5; Elevated — this CVE ranks above at least 10% of all CVEs scored today.
KEV status The KEV catalogue is a list maintained by the US authority CISA of vulnerabilities for which active exploitation in the wild has been confirmed. It answers not the question „how severe?“ but „is it already being attacked?“ — thereby sharply prioritising patching. Read in glossary: —
Published: 29.10.2026
CISA assessment (SSVC): Exploitation: none known · not automatable · Technical impact: partial; Source: CISA Vulnrichment, as of 30 October 2026
CWE CWE is a catalogue of typical weakness types in software and hardware — such as flawed input validation, unsafe memory handling or poor authentication. Where a CVE names a concrete vulnerability in a concrete product, a CWE describes the underlying class of defect. Read in glossary: CWE-552

Detection rules

No NEOSEC detection rule is available for this vulnerability yet.

Classification under NIS2 and CRA

Rule-based classification from exploitation status and severity. It does not replace a case-by-case assessment.

NIS2 NIS2 is EU Directive (EU) 2022/2555 to raise the level of cybersecurity across the Union. It substantially broadens obligations compared with the first NIS directive: more sectors, mandatory risk management, staged reporting duties and personal accountability of senior management. Read in glossary: Handle the vulnerability in regular vulnerability handling under Art. 21(2)(e) NIS2.
CRA The CRA is EU Regulation (EU) 2024/2847 setting horizontal cybersecurity requirements for „products with digital elements“ — from industrial controllers and software to connected consumer devices. For the first time manufacturers must ensure security across the entire product lifecycle, handle vulnerabilities and provide security updates. Read in glossary: From 11.12.2027, Annex I Part II CRA requires manufacturers of affected products with digital elements to handle vulnerabilities without delay and provide security updates.
ISO/IEC 27001 ISO/IEC 27001 is the internationally leading standard for an information security management system (ISMS). It describes a risk-based, process-oriented framework to systematically plan, implement, review and improve information security. Read in glossary: Control A.8.8, management of technical vulnerabilities: assess relevance to your systems, plan remediation and keep evidence.

Description

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.

Patches

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.

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.

Source: OSV (Open Source Vulnerabilities), GitHub Security Advisories, cvelistv5, NVD (NIST)

Affected products

The following versions are affected. Older releases of the same product line are also vulnerable unless stated otherwise.

Affected products
		Affected versions	Fixed in
nuxt	nuxt	`≥ 4.6.0, < 4.6.3`	—
npm	@nuxt/vite-builder	`4.6.0` `>= 4.6.0, < 4.6.3`	`4.6.3` `4.6.3`

Vendors and products

Nuxt Nuxt

Weakness classes (CWE)

CWE-552Files or Directories Accessible to External Parties
Base
The product makes files or directories accessible to unauthorized actors, even though they should not be.
Entry at MITRE CWE-552

References & sources

github.comnuxt/nuxt/commit/2981290f36d9c5412c022758f3d89ba21a845308x_refsource_MISC, web
github.comnuxt/nuxt/commit/545004cc350be7003dea4116ce6206d6f980b1fdx_refsource_MISC, web
github.comnuxt/nuxt/releases/tag/v4.6.3x_refsource_MISC, web
github.comnuxt/nuxt/security/advisories/GHSA-3xf4-9g3c-4h4wx_refsource_CONFIRM, web
NVD (NIST)vuln/detail/CVE-2026-119201advisory
github.comnuxt/nuxtpackage

Changes to this CVE

Who changed this CVE and when: NVD (analysis, affected products, CVSS), the CVE publisher (CNA) and additional providers such as CISA (ADP).

30.10.2026Record modifiedCISA ADP

CISA assessment (SSVC): exploitation: none known, automatable: no

Show the original change

Individual changes of this event as published by NVD
Type	Action	Before	After
SSVC assessment	added	—	{"id":"CVE-2026-119201","role":"CISA Coordinator","options":[{"exploitation":"none"},{"automatable":"no"},{"technicalImpact":"partial"}],"version":"2.0.3","timestamp":"2026-10-30T15:20:40.211444Z"}

Source identifier: 134c704f-9b21-4f2e-91b3-4a467353bcc0

29.10.2026ReceivedGitHub

CVSS V3.1: AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N

Weakness type: CWE-552

Description added or changed

New references:

Show 8 original changes

Individual changes of this event as published by NVD
Type	Action	Before	After
Description	added	—	Nuxt is an open-source web development framework for Vue.js. From 4.6.0 until 4.6.3, nuxt dev stores a generated appSecret in <buildDir>/app-secret, by default .nuxt/app-secret, within a directory allowed by Vite's server.fs configuration. A client with direct HTTP access to an exposed development server can fetch the file, use deriveSecret() to compute derived secrets such as the default useSession password, and forge session cookies accepted by that development server. The default localhost binding limits remote exposure, cross-origin browser reads are blocked, production builds and development servers with an explicitly configured appSecret are not affected. This issue is fixed in version 4.6.3.
CVSS	added	—	AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N
Weakness type (CWE)	added	—	CWE-552
Affected versions (publisher)	added	—	New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/119xxx/CVE-2026-119201.json">CVE-2026-119201</a>
Reference	added	—	https://github.com/nuxt/nuxt/commit/2981290f36d9c5412c022758f3d89ba21a845308
Reference	added	—	https://github.com/nuxt/nuxt/commit/545004cc350be7003dea4116ce6206d6f980b1fd
Reference	added	—	https://github.com/nuxt/nuxt/releases/tag/v4.6.3
Reference	added	—	https://github.com/nuxt/nuxt/security/advisories/GHSA-3xf4-9g3c-4h4w

Source identifier: security-advisories@github.com

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