Affected: Homebrew: codelimit

### Impact The `_uid` option performed an incomplete privilege drop on Linux/Unix-like systems.

When `sh` was run from a process with elevated privileges, such as root, and a command was launched with `_uid=<unprivileged user>`, the child process changed its UID and primary GID but did not reset its supplementary groups. As a result, the child process could retain the parent process’s supplementary groups, potentially including privileged groups such as root, docker, disk, shadow, or sudo.

This could allow a subprocess that was expected to run with reduced privileges to access files or resources available to the original process’s supplementary groups. Users are impacted if they rely on `_uid` as a privilege boundary when launching commands from a privileged parent process.

### Patches Upgrade to version >= 2.2.4

### Workarounds Avoid using `_uid` when the user represents a less-privileged user.

Affected: amoffat sh

sh provides Python process launching. Prior to 2.2.4, the _uid option in sh.py performs an incomplete privilege drop on Linux and Unix-like systems. When sh runs from an elevated process and launches a command with _uid set to an unprivileged user, the child changes its UID but can retain the parent process's supplementary groups because the privilege-drop sequence does not fully establish the target user's UID, primary GID, and supplementary groups. The child can therefore retain access to files or resources granted to privileged groups such as root, docker, disk, shadow, or sudo, violating the expected _uid privilege boundary. This issue is fixed in version 2.2.4.

Affected: PyPI: sh

### Impact The `_uid` option performed an incomplete privilege drop on Linux/Unix-like systems.

When `sh` was run from a process with elevated privileges, such as root, and a command was launched with `_uid=<unprivileged user>`, the child process changed its UID and primary GID but did not reset its supplementary groups. As a result, the child process could retain the parent process’s supplementary groups, potentially including privileged groups such as root, docker, disk, shadow, or sudo.

This could allow a subprocess that was expected to run with reduced privileges to access files or resources available to the original process’s supplementary groups. Users are impacted if they rely on `_uid` as a privilege boundary when launching commands from a privileged parent process.

### Patches Upgrade to version >= 2.2.4

### Workarounds Avoid using `_uid` when the user represents a less-privileged user.