CVE-2026-54025 LibreChat: Stored XSS via unescaped image alt text in markdown artifact preview
Attackers can inject malicious scripts via unescaped image alt text in markdown previews, executing code in victim browsers.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2026-54025?
CVE-2026-54025 is a medium-severity cross-site scripting vulnerability in Librechat Librechat, published on 25 Jun 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.
Official description
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.
Weakness: CWE-79
Which versions are affected by CVE-2026-54025?
It affects 1 product.
Products include Librechat Librechat.
How do I fix CVE-2026-54025?
No fix has been published for CVE-2026-54025 yet. Limit exposure of the affected software until one is available.
Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.
Is CVE-2026-54025 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-54025 exists.
Other vulnerabilities in Librechat Librechat
- CVE-2026-32625 LibreChat Exfiltrates Server Secrets via MCP Server URL Injection
- CVE-2024-11167 Improper Access Control in danny-avila/librechat
- CVE-2026-22252 LibreChat MCP Stdio Remote Command Execution
- CVE-2025-69222 LibreChat is vulnerable to Server-Side Request Forgery due to missing restrictions
- CVE-2024-41704 Path traversal in n/a
Sources
Also known as GHSA-3phr-62qf-cxf3.