danny-avila LibreChat up to 0.8.4-rc1/15.0.12 markdown.ts cross site scripting

Summaryinfo

A vulnerability was found in danny-avila LibreChat up to 0.8.4-rc1/15.0.12 and classified as problematic. This affects an unknown part of the file client/src/utils/markdown.ts. Such manipulation leads to cross site scripting. This vulnerability is listed as CVE-2026-54025. The attack may be performed from remote. There is no available exploit. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability was found in danny-avila LibreChat up to 0.8.4-rc1/15.0.12. It has been rated as problematic. Affected by this issue is an unknown code of the file client/src/utils/markdown.ts. The manipulation with an unknown input leads to a cross site scripting vulnerability. Using CWE to declare the problem leads to CWE-79. The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users. Impacted is integrity. CVE summarizes:

LibreChat is an enhanced ChatGPT clone that supports multiple AI providers. Prior to 0.8.4-rc1, there is a vulnerability in LibreChat's markdown artifact preview pipeline. The marked library v15.0.12 does not HTML-escape double-quote characters in image alt text when a custom renderer falls through to the default renderer. LibreChat's generateMarkdownHtml function (in client/src/utils/markdown.ts) installs a custom image renderer that returns false for URLs passing the isSafeUrl allowlist check, which causes marked to fall back to its built-in renderer. That built-in renderer inserts the raw alt text into the alt="..." attribute without escaping double-quote characters. An attacker can craft an alt text such as " onload="payload to break out of the attribute and inject an arbitrary event handler. The resulting HTML is then assigned to document.getElementById('content').innerHTML inside the Sandpack preview iframe, causing the payload to execute in the victim's browser. This vulnerability is fixed in 0.8.4-rc1.

The advisory is available at github.com. This vulnerability is handled as CVE-2026-54025 since 06/11/2026. The exploitation is known to be easy. The attack may be launched remotely. Successful exploitation requires user interaction by the victim. Technical details are known, but there is no available exploit. This vulnerability is assigned to T1059.007 by the MITRE ATT&CK project.

Upgrading to version 0.8.4-rc1 eliminates this vulnerability.

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Productinfo

Type

• Chat Software

Vendor

• danny-avila

Name

• LibreChat

Version

• 0.8.4-rc1
• 15.0.0
• 15.0.1
• 15.0.2
• 15.0.3
• 15.0.4
• 15.0.5
• 15.0.6
• 15.0.7
• 15.0.8
• 15.0.9
• 15.0.10
• 15.0.11
• 15.0.12

Website

• Product: https://github.com/danny-avila/LibreChat/

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