CVE-2026-54025
MediumCVSS 5.4Exploitation Probability (EPSS)
Low risk3th percentile — higher than 3% of all known CVEs
Summary
LibreChat prior to version 0.8.4-rc1 has a vulnerability due to missing HTML escaping of double-quote characters in image alt text in Markdown. An attacker can inject malicious HTML code that executes in the victim's browser.
Risk Assessment
The risk involves arbitrary JavaScript execution in the user's browser context, potentially leading to session theft, account takeover, or data leakage.
Recommendation
Upgrade LibreChat to version 0.8.4-rc1 or later immediately, which contains the fix for this vulnerability.
Original NVD description (English source)
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.