Impact A path traversal vulnerability exists in the Zmodem and Trzsz file download handlers in electerm. When receiving files via Zmodem or Trzsz protocols, electerm uses the remote-supplied filename directly in "path.join()" with the user-selected download directory without sanitization. A malicious SSH server or remote shell process can send a specially crafted filename such as "../escaped.txt" to escape the user-selected download directory and write files to arbitrary locations on the user's filesystem, subject to process permissions. Attack scenario: 1. User connects to a malicious SSH server 2. Attacker initiates a Zmodem or Trzsz file transfer 3. Attacker supplies a traversal filename (e.g., "../../.bashrc", "../escaped.txt") 4. User accepts the transfer and selects a download directory 5. File is written outside the selected directory, potentially overwriting sensitive files Affected components: - "src/app/server/zmodem.js" - "prepareReceiveFile()" at line 736 - "src/app/server/trzsz.js" - "getUniqueFilePath()" at line 559, "openSaveFile()" callback, and "savedFilePaths" mapping Patches - https://github.com/electerm/electerm/commit/fde153d677a170c5816368f6586647f3af4ef284 Workarounds If upgrading is not immediately possible, users can mitigate this vulnerability by: 1. Only connecting to trusted SSH servers 2. Rejecting or canceling any incoming Zmodem or Trzsz file transfers from untrusted sources 3. Avoiding the use of Zmodem ("sz"/"rz") and Trzsz ("trz"/"tsz") commands on untrusted servers