MediumCVE-2026-112948

Vitest: Files or Directories Accessible to External Parties (CVE-2026-112948)

Published 20.10.2026Last modified 20.10.2026Sources: OSV, Hersteller, CVE.org

What is affected, what to do

Update @vitest/browser to version 5.0.5, @vitest/ui to version 5.0.5, vite-plus to version 1.3.0.

Affected: Vitest gte 5.0.0-beta.6, < 5.0.5..*
@vitest Browser gte 5.0.0-beta.6, < 5.0.5..*
@vitest UI gte 5.0.0-beta.6, < 5.0.5..*
Vite-plus gte 1.0.0-rc.0, < 1.3.0..*

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Metrics

6.5

Priority

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

Source: Vendor (CNA), CVSS v3

6.5

CVSS v3

Severity Medium on the scale from 0 to 10.

Source: OSV, Hersteller, CVE.org

0.4 %

EPSS score

Low — model estimates < 1% exploitation likelihood.

Source: FIRST EPSS, percentile 34.2

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: 71.87 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: 6.5 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: 6.5
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: 0.4 %; 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: 34.2; 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: 20.10.2026
CISA assessment (SSVC): Exploitation: none known · not automatable · Technical impact: partial; Source: CISA Vulnrichment, as of 20 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-200, 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

Summary

In Vitest 5, Vite's server.fs.deny is not applied as intended on Vitest's dev servers. Depending on the server, files that Vite refuses to serve by default (such as .env, private keys and certificates, .npmrc, and .git) or Vitest's own API token file (.vitest-secret-token) can be read over plain HTTP by a client that can reach the server. In Browser Mode with test.projects, a malicious website can also read .env values through the developer's browser.

This only applies when Vitest runs an HTTP server, which happens with the UI (--ui), Browser Mode, or api enabled. Plain vitest and vitest run don't listen on any port and are not affected. The fix ships in vitest, and @vitest/ui and @vitest/browser are listed because they are what enables the affected setups. Both pin vitest to the same version as a peer dependency, so upgrading either one also requires the patched vitest. Users who enable api without @vitest/ui or @vitest/browser are also affected and should upgrade vitest.

Details

Vitest 5 adds its API token file to server.fs.deny, but neither server ended up with the intended list. That's because of two Vite behaviors. Vite applies its default deny list only when server.fs.deny is unset, and it compiles the list into a matcher during config resolution, so later changes to the array have no effect.

setup	listening server	Vite's default deny list	`.vitest-secret-token`
plain `vitest` / `vitest run`	none	not reachable	not reachable
`--ui` or `api`	root	denied	served (fallback location only)
Browser Mode, single project	root (also the browser server)	denied	served (fallback location only)
Browser Mode with `test.projects`	each browser project's server	served	denied

Project servers set deny: ['.vitest-secret-token'] from a config() hook, which replaces Vite's defaults. A project server listens on a port in Browser Mode with test.projects, so in that setup a request like GET /.env?raw returns the file. A plain GET /.env is also served as text/javascript, so a malicious page can include it with <script src="http://localhost:<port>/.env">. A classic script include needs no CORS, and each dotenv line whose value is valid JavaScript (a quoted string, number, or boolean) runs as a global assignment the page can read. A syntax error anywhere in the file, such as a # comment, keeps the whole script from running. The same missing defaults also loosen Browser Mode's file-access checks for server.readFile/writeFile/removeFile, screenshots, and traces.
The root server adds the token entry after Vite has compiled the matcher, so the entry is never applied. The token file normally lives in the per-user data directory, which is outside server.fs.allow. When that directory can't be written, for example in a container whose user has no writable HOME, Vitest falls back to <workspaceRoot>/node_modules/.vitest/.vitest-secret-token, which the root server then serves. The token authenticates the UI, /__vitest_attachment__, and the API WebSocket, whose RPC can write and rerun test files when api.allowWrite/api.allowExec are enabled.

Impact

Information disclosure from the Vitest dev server, and with the token, privileged API access.

From a malicious website, in Browser Mode with test.projects: while the browser server runs, any page the developer visits can read .env values that are valid JavaScript, through a classic <script> include. This works when the file consists of KEY="value" lines. An unquoted value causes a runtime error that stops the script at that line, so only the lines before it leak. A syntax error anywhere in the file, such as a # comment line or an export prefix, prevents the script from running at all. Recent Chrome versions may ask for Local Network Access permission first. fetch and XHR reads from other websites are still blocked by Vite's default CORS policy, and Vite's Host check blocks DNS rebinding. That CORS policy does allow localhost origins, so a page served from another local dev server could read full files. The token file can't be read through a classic <script>, because a bare token isn't valid JavaScript.
With local access or developer-set network exposure (such as api.host or browser.api.host, port forwarding, or a published container port): full file contents are readable over plain HTTP, including the token file when it's in the fallback location.

Only the machine running Vitest is exposed, while it runs one of the setups above. Applications built or deployed from the project aren't affected.

The fix is in vitest <PATCHED>. Vitest 4 and earlier are unaffected. They don't persist an API token, and they don't override server.fs.deny.

Workaround

Set server.fs.deny explicitly in the root Vitest config, including Vite's default list for your Vite version and the token file. For Vite 8.3:

export default defineConfig({
  server: {
    fs: {
      deny: [
        '.env',
        '.env.*',
        '*.{crt,pem,key,p12,pfx,cer,der}',
        '.npmrc',
        '.yarnrc.yml',
        '**/.git/**',
        '.vitest-secret-token',
      ],
    },
  },
})

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
@vitest	browser	`≥ 5.0.0-beta.6, < 5.0.5`	—
@vitest	ui	`≥ 5.0.0-beta.6, < 5.0.5`	—
vitejs	vite-plus	`≥ 1.0.0-rc.0, < 1.3.0`	—
vitest-dev	vitest	`≥ 5.0.0-beta.6, < 5.0.5`	—
npm	@vitest/browser	`>= 5.0.0-beta.6, < 5.0.5` `5.0.0-beta.6`	`5.0.5` `5.0.5`
npm	@vitest/ui	`5.0.0-beta.6` `>= 5.0.0-beta.6, < 5.0.5`	`5.0.5` `5.0.5`
npm	vite-plus	`1.0.0-rc.0` `>= 1.0.0-rc.0, < 1.3.0`	`1.3.0` `1.3.0`

Vendors and products

Weakness classes (CWE)

CWE-200Exposure of Sensitive Information to an Unauthorized Actor
Class
The product exposes sensitive information to an actor that is not explicitly authorized to have access to that information.
Entry at MITRE CWE-200
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.comvitest-dev/vitest/commit/28dc1edfb6ba5a181fe208576989063795aead…x_refsource_MISC, web
github.comvitest-dev/vitest/pull/11578x_refsource_MISC, web
github.comvitest-dev/vitest/releases/tag/v5.0.5x_refsource_MISC, web
github.comvitest-dev/vitest/security/advisories/GHSA-p458-7748-mcp3x_refsource_CONFIRM, web
NVD (NIST)vuln/detail/CVE-2026-112948advisory
github.comvitest-dev/vitestpackage

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).

20.10.2026Record 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-2026-112948","role":"CISA Coordinator","options":[{"exploitation":"none"},{"automatable":"no"},{"technicalImpact":"partial"}],"version":"2.0.3","timestamp":"2026-10-20T16:16:51.150771Z"}

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

20.10.2026ReceivedGitHub

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

Weakness type: CWE-200, CWE-552

Description added or changed

New references:

Show 9 original changes

Individual changes of this event as published by NVD
Type	Action	Before	After
Description	added	—	Vitest is a testing framework powered by Vite. From 5.0.0-beta.6 until 5.0.5, Vitest dev servers can misapply server.fs.deny because project servers replace Vite's defaults and the root server adds .vitest-secret-token after Vite compiles its matcher. An attacker who can reach an affected UI, Browser Mode, or API server can read denied project files or the fallback API token at node_modules/.vitest/.vitest-secret-token, and Browser Mode with test.projects can expose JavaScript-compatible .env values through a malicious website. This issue is fixed in version 5.0.5.
CVSS	added	—	AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N
Weakness type (CWE)	added	—	CWE-200
Weakness type (CWE)	added	—	CWE-552
Affected versions (publisher)	added	—	New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/112xxx/CVE-2026-112948.json">CVE-2026-112948</a>
Reference	added	—	https://github.com/vitest-dev/vitest/commit/28dc1edfb6ba5a181fe208576989063795aeadb3
Reference	added	—	https://github.com/vitest-dev/vitest/pull/11578
Reference	added	—	https://github.com/vitest-dev/vitest/releases/tag/v5.0.5
Reference	added	—	https://github.com/vitest-dev/vitest/security/advisories/GHSA-p458-7748-mcp3

Source identifier: security-advisories@github.com

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