OpenClaw: Sandbox media fallback tmp symlink alias bypass allows host file reads outside sandboxRoot

Summary

A sandbox path validation bypass in openclaw allows host file reads outside sandboxRoot via the media path fallback tmp flow when the fallback tmp root is a symlink alias.

Affected Packages / Versions

• Package: npm openclaw
• Affected versions: <= 2026.2.24
• Latest published npm version at triage time (February 26, 2026): 2026.2.24
• Patched version : 2026.2.25

Details

When /tmp/openclaw is unavailable or unsafe, resolvePreferredOpenClawTmpDir() in src/infra/tmp-openclaw-dir.ts fell back to os.tmpdir()/openclaw-<uid> without verifying that fallback path was a trusted non-symlink directory.

resolveSandboxedMediaSource() (src/agents/sandbox-paths.ts) allows absolute tmp media paths under the OpenClaw tmp root using lexical containment and alias checks. If the fallback tmp root is a symlink alias (for example to /), inputs like $TMPDIR/openclaw-<uid>/etc/passwd can pass validation and resolve to host files outside sandboxRoot.

Impact

This can break sandbox media path confinement and permit unauthorized host file reads (confidentiality impact).

Reproduction (high level)

1. Force resolver fallback (make /tmp/openclaw unavailable/invalid).
2. Make fallback root ($TMPDIR/openclaw-<uid>) a symlink alias to /.
3. Submit media path under fallback root (for example $TMPDIR/openclaw-<uid>/etc/passwd).
4. Observe accepted path and read outside sandboxRoot.

Fix Commit(s)

• 496a76c03ba85e15ea715e5a583e498ae04d36e3

Release Process Note

Patched version is pre-set to release 2026.2.25; once npm publish for 2026.2.25 is complete, this advisory can be published without further metadata edits.

OpenClaw thanks @tdjackey for reporting.