Vulnerability · Published Dec 11, 2025 · Assigned by GitHub_M

CVE-2025-66452LibreChat's lack of JSON parsing error handling can lead to XSS

Medium 5.3

In plain English

A medium-severity cross-site scripting in LibreChat from danny-avila. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 12% of all known vulnerabilities).

Severity (CVSS 4.0)5.3Medium

Exploit odds (30 days)0.2%top 87.9% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

Official description

LibreChat is a ChatGPT clone with additional features. In versions 0.8.0 and below, there is no handler for JSON parsing errors; SyntaxError from express.json() includes user input in the error message, which gets reflected in responses. User input (including HTML/JavaScript) can be exposed in error responses, creating an XSS risk if Content-Type isn't strictly enforced. This issue does not have a fix at the time of publication.

Affected products (as reported)

Vendor	Product	Versions
danny-avila	LibreChat	<= 0.8.1

Weakness: CWE-79 · Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N

References

https://github.com/danny-avila/LibreChat/security/advisories/GHSA-q6c5-gvj5-c264 x_refsource_CONFIRM