Joplin version 2.8.8 allows an external attacker to execute arbitrary commands remotely on any client that opens a link in a malicious markdown file, via Joplin. This is possible because the application does not properly validate the schema/protocol of existing links in the markdown file before passing them to the 'shell.openExternal' function.

Joplin v2.8.8 allows attackers to execute arbitrary commands via a crafted payload injected into the Node titles.