CVE-2026-43943: Electerm Security Vulnerability: RCE via malicious SSH server filename in openFileWithEditor

A code execution (RCE) vulnerability exists in electerm’s SFTP open with system editor or “Edit with custom editor” feature. When a user opts to edit a file using open with system editor or open with a custom editor, the filename is passed directly into a command line without sanitization.

A malicious actor controlling the SSH server or user OS can exploit this by crafting a filename containing shell metacharacters. If a victim subsequently attempts to edit this file, the injected commands are executed on their machine with the user’s privileges. This could allow the attacker to run arbitrary code, install malware, or move laterally within the network.