CVE-2026-49864: CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') in butlerx wetty
CVE-2026-49864 is a high-severity cross-site scripting (XSS) vulnerability in the wetty client prior to version 3.0.4. The vulnerability arises because the client decodes a base64 filename from a file-download escape sequence and inserts it directly into an HTML string without escaping, allowing attacker-controlled script execution. This can lead to script execution in the context of the wetty origin and unauthorized keystroke injection into the victim's SSH session. The issue is fixed in version 3.0.4.
AI Analysis
Technical Summary
The wetty client in versions before 3.0.4 improperly neutralizes input during web page generation by decoding a base64 filename from a file-download escape sequence and interpolating it raw into a Toastify HTML string with escapeMarkup disabled. This allows an attacker to craft input containing specific escape sequences (`\x1b[5i...:...\x1b[4i`) that execute arbitrary scripts in the wetty origin context and inject keystrokes into the victim's SSH session. The vulnerability is classified as CWE-79 (Improper Neutralization of Input During Web Page Generation). Version 3.0.4 addresses this issue.
Potential Impact
Successful exploitation allows an attacker to execute arbitrary scripts in the context of the wetty web client and inject attacker-chosen keystrokes into the victim's SSH session. This can lead to unauthorized command execution within the victim's SSH session. The CVSS 4.0 base score is 8.6 (high), reflecting network attack vector, no privileges required, user interaction required, and high impact on confidentiality and integrity.
Mitigation Recommendations
Upgrade wetty to version 3.0.4 or later, where this vulnerability is fixed. No other official remediation or temporary fixes are documented. Patch status is not explicitly stated but the fix is included in version 3.0.4. Users should apply this update promptly to mitigate the risk.
CVE-2026-49864: CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') in butlerx wetty
Description
CVE-2026-49864 is a high-severity cross-site scripting (XSS) vulnerability in the wetty client prior to version 3.0.4. The vulnerability arises because the client decodes a base64 filename from a file-download escape sequence and inserts it directly into an HTML string without escaping, allowing attacker-controlled script execution. This can lead to script execution in the context of the wetty origin and unauthorized keystroke injection into the victim's SSH session. The issue is fixed in version 3.0.4.
CVSS v4.0
Score 8.6high
Affected software
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The wetty client in versions before 3.0.4 improperly neutralizes input during web page generation by decoding a base64 filename from a file-download escape sequence and interpolating it raw into a Toastify HTML string with escapeMarkup disabled. This allows an attacker to craft input containing specific escape sequences (`\x1b[5i...:...\x1b[4i`) that execute arbitrary scripts in the wetty origin context and inject keystrokes into the victim's SSH session. The vulnerability is classified as CWE-79 (Improper Neutralization of Input During Web Page Generation). Version 3.0.4 addresses this issue.
Potential Impact
Successful exploitation allows an attacker to execute arbitrary scripts in the context of the wetty web client and inject attacker-chosen keystrokes into the victim's SSH session. This can lead to unauthorized command execution within the victim's SSH session. The CVSS 4.0 base score is 8.6 (high), reflecting network attack vector, no privileges required, user interaction required, and high impact on confidentiality and integrity.
Mitigation Recommendations
Upgrade wetty to version 3.0.4 or later, where this vulnerability is fixed. No other official remediation or temporary fixes are documented. Patch status is not explicitly stated but the fix is included in version 3.0.4. Users should apply this update promptly to mitigate the risk.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-06-01T22:03:19.640Z
- Cvss Version
- 4.0
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6a7e1a7fbf8831d539b180dd
Added to database: 08/13/2026, 19:26:55 UTC
Last enriched: 08/13/2026, 19:56:36 UTC
Last updated: 08/13/2026, 19:56:36 UTC
Views: 2
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