CVE-2026-49864
High
Description
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.
SeverityHigh
CVSS8.6
Exploit probability—
ProductWetty
PublishedAug 13, 2026
First seenAug 13, 2026
Weakness typeCWE-79Cross-site scripting (XSS)
How to fix
Update
- wetty3.0.4 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| wettynpm | v < 3.0.4 | 3.0.4 |
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