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TI-2025-40884 Aliases CVE-2025-66452

LibreChat's lack of JSON parsing error handling can lead to XSS

Priority MEDIUM 57CWE-79Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
Passive
Attack complexity
Low
Attack requirements
None
Impact type
Cross-site scripting
Confidentiality · integrity · availability
Low · Low · None
Fix status
No fix listed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-79.

Summary

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.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00216 12th percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix No fix listed No fixed version in the sources yet

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
danny-avilaLibreChatup to 0.8.1—No fix listedCNA
  • LibreChat Vendordanny-avila Affected up to 0.8.1 Fixed in — No fix listed CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:librechat:librechat:*:*:*:*:*:*:*:*up to 0.8.0Vulnerabledanny-avila
  • cpe:2.3:a:librechat:librechat:*:*:*:*:*:*:*:* Versions up to 0.8.0 Vulnerable ·danny-avila

Remediation

No fixed version listed by the sources yet.

Timeline

  1. 2026-10-02 Threatist record created from CVE-2025-66452

References

Exploit 1

  • TI-2026-25134 LibreChat Exfiltrates Server Secrets via MCP Server URL Injection CVSS 3.1CRITICAL 9.6
  • TI-2026-17862 LibreChat MCP Stdio Remote Command Execution CVSS 3.1CRITICAL 9.9
  • TI-2026-38976 LibreChat: Missing Resource Parameter Validation in MCP OAuth Flow CVSS 3.1CRITICAL 9.3
  • TI-2024-27763 LibreChat through 0.7.4-rc1 has incorrect access control for message updates. CVSS 3.1CRITICAL 9.8
  • TI-2024-10347 Path Traversal in danny-avila/librechat CVSS 3.0HIGH 8.8
  • TI-2026-25682 In LibreChat 0.8.1-rc2, a logged-in user obtains a JWT for both the LibreChat API and the RAG API. CVSS 3.1CRITICAL 9.0
See all 50 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences