# CVE-2026-123829: Node.js is vulnerable to Permission Model file-name disclosure via recursive fs.watch

> Code running under Node.js Permission Model can learn names of files it is denied to read via recursive fs.watch on macOS or Windows.

- **Severity:** Low 2.5 (`CVSS:3.0/AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Harmful if only installed:** No
- **Needs a specific call:** Yes (`fs.watch()`, `fs.promises.watch()`)
- **Fix available:** Yes
- **Published:** 11 Nov 2026
- **Updated:** 11 Nov 2026
- **Also known as:** ALPINE-CVE-2026-123829, BELL-CVE-2026-123829, DEBIAN-CVE-2026-123829, GHSA-fxj5-xgw6-cx7g, UBUNTU-CVE-2026-123829

## What is CVE-2026-123829?

CVE-2026-123829 is a low-severity information disclosure vulnerability in nodejs node, published on 11 Nov 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

A Permission Model bypass in Node.js recursive file watching discloses the names of files and directories the process is not permitted to read. On macOS and Windows, fs.watch() and fs.promises.watch() in recursive mode are backed by the native libuv watcher: FSEventWrap::Start checks kFileSystemRead only once, on the watched root, and FSEventWrap::OnEvent then forwards every filename libuv reports (relative paths at any depth) to the JavaScript callback without checking that each path is covered by the read grant. Code running under --permission with an exact read grant on a directory can therefore learn names such as sub/secret.txt even though readdir on that subdirectory is denied. The flaw exposes names and timing metadata, not file contents, and requires macOS or Windows plus files created under the watched directory by another actor. This vulnerability affects Node.js 26.x, 24.x, and 22.x.

Weakness: CWE-200 (Exposure of Sensitive Information to an Unauthorized Actor)

## Which versions are affected by CVE-2026-123829?

An affected version is only exploitable if your software calls fs.watch() or fs.promises.watch(). Many projects that include it are not exposed.


## How do I fix CVE-2026-123829?

No fix published yet.

## Is CVE-2026-123829 being exploited?

There is no known exploitation of CVE-2026-123829 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-123829 and fix it if it is affected.

What it is: CVE-2026-123829 is a low-severity information disclosure vulnerability in nodejs node, published on 11 Nov 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-123829 in the wild and no public exploit code.
Exposure: An affected version is only exploitable if your software calls fs.watch() or fs.promises.watch(). Many projects that include it are not exposed.

Affected product: nodejs node. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
   If an affected version is present, also search the code for calls to fs.watch() or fs.promises.watch() and report whether any exist.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-123829/ (Markdown: https://insights.sbomify.com/CVE-2026-123829/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-123829
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-123829
- OSV: https://osv.dev/vulnerability/CVE-2026-123829

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-123829/
Summaries are generated and may contain mistakes; the official description above is the record.