CVE-2026-54025
LibreChat: Stored XSS via unescaped image alt text in markdown artifact preview
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.
INFO
Published Date :
June 25, 2026, 5:16 p.m.
Last Modified :
June 29, 2026, 4:02 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | MEDIUM | [email protected] |
Solution
- Update LibreChat to version 0.8.4-rc1 or later.
- Review and sanitize markdown rendering processes.
- Ensure all user-supplied input is properly escaped.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-54025.
| URL | Resource |
|---|---|
| https://github.com/danny-avila/LibreChat/security/advisories/GHSA-3phr-62qf-cxf3 | Exploit Mitigation Vendor Advisory |
| https://github.com/danny-avila/LibreChat/security/advisories/GHSA-3phr-62qf-cxf3 | Exploit Mitigation Vendor Advisory |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-54025 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-54025
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-54025 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-54025 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
Initial Analysis by [email protected]
Jun. 29, 2026
Action Type Old Value New Value Added CPE Configuration OR *cpe:2.3:a:librechat:librechat:*:*:*:*:*:*:*:* versions up to (including) 0.7.8 Added Reference Type GitHub, Inc.: https://github.com/danny-avila/LibreChat/security/advisories/GHSA-3phr-62qf-cxf3 Types: Exploit, Mitigation, Vendor Advisory Added Reference Type CISA-ADP: https://github.com/danny-avila/LibreChat/security/advisories/GHSA-3phr-62qf-cxf3 Types: Exploit, Mitigation, Vendor Advisory -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jun. 25, 2026
Action Type Old Value New Value Added Reference https://github.com/danny-avila/LibreChat/security/advisories/GHSA-3phr-62qf-cxf3 Added SSVC {'id': 'CVE-2026-54025', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'poc'}, {'automatable': 'no'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-06-25T18:02:07.544932Z'} -
New CVE Received by [email protected]
Jun. 25, 2026
Action Type Old Value New Value Added Affected [{'vendor': 'danny-avila', 'product': 'LibreChat', 'versions': [{'status': 'affected', 'version': '< 0.8.4-rc1'}]}] Added 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. Added CVSS V3.1 AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N Added CWE CWE-79 Added Reference https://github.com/danny-avila/LibreChat/security/advisories/GHSA-3phr-62qf-cxf3