wetty vulnerable to DOM XSS via file-download filename (CVE-2026-49864) | HOL Guard CVE

High · CVSS 8.6CVE-2026-49864GHSA-P26J-H7WJ-R568

wetty vulnerable to DOM XSS via file-download filename

Answer in brief

CVE-2026-49864 records a High severity (CVSS 8.6) vulnerability in wetty vulnerable to DOM XSS via file-download filename. The current sources do not mark it as known exploited. The current feed maps butlerx/wetty (generic), wetty (npm). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Aug 13, 2026Updated Sep 9, 2026Source checked Sep 17, 2026First seen by HOL Jul 1, 2026Material review Sep 9, 2026

Upstream Advisory

Key facts

Risk: High · CVSS 8.6
Exploitation: Not marked as known exploited
Affected software: 2 mapped packages or products
Fix availability: Available

Why this deserves its current priority

CVSS is 8.6. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps butlerx/wetty (generic), wetty (npm). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
butlerx/wettygeneric	< 3.0.4	Not reported
wettynpm	<3.0.4	3.0.4

Recommended response

Check inventory. Check lockfiles and deployed manifests for butlerx/wetty, wetty.
Review the reported fix. Update wetty to 3.0.4 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Aug 13, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Sep 9, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Jul 1, 2026

Sources and claim methodology

Upstream source 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.

Quoted source text, attributed separately from HOL analysis.