Unvalidated shell.openExternal in electerm allows arbitrary protocol execution via terminal link click

electerm is an open-sourced terminal/ssh/sftp/telnet/serialport/RDP/VNC/Spice/ftp client. In versions 3.8.15 and prior, Electerm's terminal hyperlink handler passes any URL clicked in the terminal directly to shell.openExternal without any protocol validation. An attacker who controls terminal output (e.g., via a malicious SSH server, compromised remote host, or malicious plugin rendering terminal content) can thus achieve arbitrary code execution or local file access on the victim's machine, requiring only that the victim clicks a displayed link. At time of publication, there are no publicly available patches.