humanfs: Recursive copy follows symlinked files and copies data from outside the source tree

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS 4.0

5.7 · CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:P/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N · score source

EPSS

No dated EPSS signal available.

As published by the source; long descriptions are shortened.

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…

Published by the source

2 Sep 2026, 14:27 UTC

Last modified by the source

2 Sep 2026, 14:27 UTC

Source last checked

26 Oct 2026, 13:02 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-p498-v437-472g

Preview the exact text before you copy it. Commands are read-only suggestions; review them before running anything.

# Patch Next advisory brief: GHSA-p498-v437-472g

Advisory: humanfs: Recursive copy follows symlinked files and copies data from outside the source tree
IDs: GHSA-p498-v437-472g
Record: https://patchnext.com/advisories/ghsa-p498-v437-472g (revision 1, source checked 26 Oct 2026, 13:02 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 5.7)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: @humanfs/node 0.16.8. A vendor fix does not mean a deployment is fixed.

## Affected components
- npm @humanfs/node: affected < 0.16.8; fixed in 0.16.8

## Suggested inspection (read-only)
- `npm ls @humanfs/node --all`: lists every installed copy and version, including transitive ones. Run in the project root after `npm ci`.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on @humanfs/node.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-p498-v437-472g (GitHub-reviewed advisory GHSA-p498-v437-472g lists affected ranges: npm @humanfs/node >=0 <0.16.8)

Commands are suggestions: review each one before running it.