CVE-2025-54288: Canonical LXD Source Container Identification Vulnerability via cmdline Spoofing in devLXD Server

In LXD’s devLXD server, the source container identification process uses process cmdline (command line) information, allowing attackers to impersonate other containers by spoofing process names.

The core issue lies in the findContainerForPID function in lxd/api_devlxd.go. This function identifies senders through two steps as shown below:

1. cmdline-based identification: Check while tracing back through parent processes, and if it starts with [lxc monitor], extract the project name and container name from that process name in the format projectName_containerName.
2. PID namespace-based identification: If not found in Step 1, check against all containers’ PID namespaces.

https://github.com/canonical/lxd/blob/43d5189564d27f6161b430ed258c8b56603c2759/lxd/api_devlxd.go#L166-L276

Attackers can exploit Step 1 processing to impersonate arbitrary containers across projects by spoofing process names.