Openclaw cli: OpenClaw: shell-env trusted-prefix fallback allowed attacker-controlled binary execution via $SHELL (CVE-2026-22217)

OpenClaw CLI's shell-env fallback mechanism allowed selection of a shell executable either from /etc/shells or from hardcoded trusted prefixes (/bin, /usr/bin, /usr/local/bin, /opt/homebrew/bin, /run/current-system/sw/bin). This fallback permitted execution of attacker-controlled binaries if an attacker could influence the $SHELL environment variable and if any of these trusted prefix directories were writable, such as common Homebrew layouts under /opt/homebrew/bin. The selected shell was executed as a login shell for environment probing, enabling local or runtime environment attackers to execute arbitrary binaries in the OpenClaw process context. The vulnerability is tracked as CVE-2026-22217 and has a CVSS 3.1 score of 6.1 (medium severity). The fix, released in version 2026.2.23, removes the trusted-prefix fallback and restricts shell selection to those explicitly registered in /etc/shells or defaults to /bin/sh.

An attacker with local or runtime environment influence can execute arbitrary binaries in the context of the OpenClaw process by manipulating the $SHELL environment variable when a trusted prefix directory is writable. This can lead to integrity compromise of the affected system or process. The vulnerability does not impact confidentiality but has a high impact on integrity and a low impact on availability.

A patch is available and has been released in OpenClaw CLI version 2026.2.23. Users should upgrade to version 2026.2.23 or later to remediate this vulnerability. The fix removes the fallback to trusted-prefix directories and restricts shell selection to shells explicitly listed in /etc/shells or defaults to /bin/sh, preventing execution of attacker-controlled binaries via $SHELL manipulation.