OpenClaw: shell-env trusted-prefix fallback allowed attacker-controlled binary execution via $SHELL

Summary

shell-env fallback trusted prefix-based executable paths for $SHELL, allowing execution of attacker-controlled binaries in local/runtime-env influence scenarios.

Details

In affected versions, shell selection accepted either:

1. a shell listed in /etc/shells, or
2. any executable under hardcoded trusted prefixes (/bin, /usr/bin, /usr/local/bin, /opt/homebrew/bin, /run/current-system/sw/bin).

The selected shell was then executed as a login shell (-l -c 'env -0') for PATH/environment probing.

On systems where a trusted-prefix directory is writable (for example common Homebrew layouts under /opt/homebrew/bin) and runtime $SHELL can be influenced, this enabled attacker-controlled binary execution in OpenClaw process context.

The fix removes the trusted-prefix executable fallback and now trusts only shells explicitly registered in /etc/shells; otherwise it falls back to /bin/sh.

Affected Packages / Versions

• Package: openclaw (npm)
• Affected versions: >= 2026.2.22, <= 2026.2.22-2
• Latest published vulnerable version: 2026.2.22-2
• Patched versions (released): >= 2026.2.23

Fix Commit(s)

• ff10fe8b91670044a6bb0cd85deb736a0ec8fb55

Release Process Note

This advisory sets patched_versions to the released version (2026.2.23).
This advisory now reflects released fix version 2026.2.23.

OpenClaw thanks @tdjackey for reporting.