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CVE-2026-31943

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

Published: Mar 27, 2026Updated: Mar 31, 2026 Sources: CVE List NVDCWE-918
NVD MITRE
8.5CVSSHIGH
EPSS Score
0.2%
Top 88.6%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
Patch Available

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.

CVSS Vector Breakdown

AV:NAC:LPR:LUI:NS:CC:HI:LA:N
Exploitability
AV:NAttack Vector
Network
AC:LAttack Complexity
Low
PR:LPrivileges Required
Low
UI:NUser Interaction
None
Scope
S:CScope
Changed
Impact
C:HConfidentiality
High
I:LIntegrity
Low
A:NAvailability
None
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Weaknesses

CWE-918

Affected Products

librechatlibrechat
Mixed
Communications / messaging-chat
LibreChatdanny-avila
Mixed
Communications / messaging-chat
librechatoss-projectCommunications
danny-avilaindividual-devCommunicationsaka danny-avila/librechat, librechat

Attack Graph

Products CVE Techniques Tactics

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Exploitability

Official Patch Available

MITRE ATT&CK

2 techniques
Command and Control
Initial Access
View detailed technique mapping

References

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

Timeline

Published
Mar 27, 2026
Last Updated
Mar 31, 2026

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