CVE-2026-31943

LibreChat has SSRF protection bypass via IPv4-mapped IPv6 normalization in isPrivateIP

State: Published
Severity: 8.5 High
Published: Mar 27, 2026
Updated: Mar 31, 2026
Reserved: Mar 10, 2026

Description

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.

Scores

CVSS	Score	Vector	Source
3.1	8.5 High	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:N	GitHub_M

Weaknesses

CWE-918 Server-Side Request Forgery (SSRF)

Affected Products

Product	Versions
LibreChatdanny-avila	< 0.8.3Affected

References

https://github.com/danny-avila/LibreChat/security/advisories/GHSA-w5r7-4f94-vp4c

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