Vulnerability · Published Aug 13, 2026 · Assigned by GitHub_M

CVE-2026-49864wetty vulnerable to DOM XSS via file-download filename

High 8.6

In plain English

A high-severity cross-site scripting in wetty from butlerx. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 39% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 4.0)8.6High

Exploit odds (30 days)0.4%top 61.2% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

Official 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.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
npm	wetty	3.0.4	GHSA-p26j-h7wj-r568

Affected products (as reported)

Vendor	Product	Versions
butlerx	wetty	< 3.0.4

Weakness: CWE-79 · Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:L/SC:N/SI:N/SA:N

References

https://github.com/butlerx/wetty/security/advisories/GHSA-p26j-h7wj-r568 x_refsource_CONFIRM