# GHSA-p498-v437-472g: humanfs: Recursive copy follows symlinked files and copies data from outside the source tree

> Attackers can use symlinks in source directories to copy arbitrary host files into destinations via the humanfs library, leading to information disclosure.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Not stated
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 2 Sep 2026

## What is GHSA-p498-v437-472g?

GHSA-p498-v437-472g is a path traversal vulnerability in @humanfs/node, published on 2 Sep 2026. 

### Official description

### Summary

`@humanfs/node` does not treat symlinks as a separate case during copy operations. A symlink placed inside an attacker-controlled source tree can make `copyAll()` read and copy the contents of any file readable by the process, even when that file is outside the directory being copied.

### Details

The Node implementation exposes symlink state through `list()`, but `copyAll()` ignores it. During recursive copies, every non-directory entry is passed to `copy()`, which delegates to `fs.promises.copyFile()`.

On Node, `copyFile()` dereferences symlinks. As a result, a symlink inside the copied tree is handled as if it were an ordinary file, and the destination receives the contents of the symlink target rather than a copy of the link itself.

That breaks the expected boundary of a directory copy. A caller can point `copyAll()` at a seemingly self-contained directory and still end up copying data from elsewhere on the host filesystem if the source tree contains attacker-supplied symlinks.

The same dereference behavior also affects `copy()` when the source path itself is a symlink.

### PoC

```js
import { NodeHfs } from "@humanfs/node";
import fs from "node:fs/promises";
import path from "node:path";
import os from "node:os";

const root = await fs.mkdtemp(path.join(os.tmpdir(), "humanfs-"));
const src = path.join(root, "src");
const dst = path.join(root, "dst");
const secret = path.join(root, "secret.txt");

await fs.mkdir(src);
await fs.writeFile(secret, "TOPSECRET");
await fs.symlink(secret, path.join(src, "link.txt"));

const hfs = new NodeHfs();
await hfs.copyAll(src, dst);

console.log(await fs.readFile(path.join(dst, "link.txt"), "utf8"));
// TOPSECRET
```

### Impact

If an application uses `copyAll()` or `copy()` on attacker-controlled paths, a symlink can be used to pull arbitrary readable host files into the copied output. In practice, that can turn a normal workspace copy, export, or packaging step into a file disclosure primitive.

## Which versions are affected by GHSA-p498-v437-472g?

2 open source packages ship an affected version, including @humanfs/node.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `@humanfs/node` | npm | All versions | 0.16.8 |
| `@humanfs/node` | npm | All versions | 0.16.8 |

## How do I fix GHSA-p498-v437-472g?

Upgrade @humanfs/node to 0.16.8 or later.

## Is GHSA-p498-v437-472g being exploited?

There is no known exploitation of GHSA-p498-v437-472g in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for GHSA-p498-v437-472g and fix it if it is affected.

What it is: GHSA-p498-v437-472g is a path traversal vulnerability in @humanfs/node, published on 2 Sep 2026. 
Exploitation: There is no known exploitation of GHSA-p498-v437-472g in the wild and no public exploit code.

Affected packages and fixed versions:
- @humanfs/node (npm): affected all versions; fixed in 0.16.8
- @humanfs/node (npm): affected all versions; fixed in 0.16.8

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.
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/GHSA-p498-v437-472g/ (Markdown: https://insights.sbomify.com/GHSA-p498-v437-472g/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/GHSA-p498-v437-472g

---
From sbomify Insights: https://insights.sbomify.com/GHSA-p498-v437-472g/
Summaries are generated and may contain mistakes; the official description above is the record.