CVE-2026-31943: Librechat

High severity, CVSS 8.5. EPSS: 0.3% chance of exploitation in the next 30 days.

LibreChat is a ChatGPT clone with additional features. Prior to version 0.8.3, `isPrivateIP()` in `packages/api/src/auth/domain.ts` fails to detect IPv4-mapped IPv6 addresses in their hex-normalized form, allowing any authenticated user to bypass SSRF protection and make the server issue HTTP requests to internal network resources — including cloud metadata services (e.g., AWS `169.254.169.254`), loopback, and RFC1918 ranges. Version 0.8.3 fixes the issue.

Affected products

• Librechat Librechat: before 0.8.3 (fixed in 0.8.3); version 0.8.3 only

Published 2026-03-27. Last modified 2026-06-17.