CVE-2026-31943 HIGH

CVE-2026-31943: LibreChat has SSRF protection bypass via IPv4-mapped IPv6 normalization in isPrivateIP

Vendor Danny-Avila
Product LibreChat
Weakness CWE-918 · SSRF
Published March 27, 2026
Last update March 31, 2026
View on NVD All CVEs

CVSS base score

8.5/10
Attack vector Network
Attack complexity Low
Privileges required Low
User interaction None
Confidentiality High
Integrity Low

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:N

What the vulnerability does

01Description

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.

Key dates

02Disclosure timeline

March 27, 2026 CVE published
March 31, 2026 Record updated