Logseq exposes an IPC handler that allows the renderer process to execute shell commands. While an allowlist restricts the command name (e.g. git, pandoc, grep), the argument string is concatenated with the command and passed to child_process.spawn with the shell: true option, allowing shell metacharacters in the arguments to bypass the allowlist. An attacker with JavaScript execution in the renderer (e.g. via XSS or a malicious plugin) can execute arbitrary shell commands with the privileges of the Logseq process, leading to remote code execution on the host.
While only version v0.10.15 was tested and confirmed as vulnerable, status of other versions is unknown since this issue was not addressed by a patch.