CVE-2026-49864

wetty provides terminal access in browser over http/https. Prior to version 3.0.4, the wetty client decodes a base64 filename from the file-download escape sequence and interpolates it raw into a Toastify HTML string (escapeMarkup: false). Any output the victim renders - a cat'd file, a tailed log, an SSH MOTD, a curl response - that contains \x1b[5i...:...\x1b[4i runs script in the wetty origin and types attacker-chosen keystrokes into the victim's SSH session. Version 3.0.4 fixes the issue.