CVE-2026-31943 json
LibreChat has SSRF protection bypass via IPv4-mapped IPv6 normalization in isPrivateIP
published 2026-03-27 7 mo ago modified 2026-10-26 13 d ago also EUVD-2026-16764
- cvss
- 8.5
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.2%
- EPSS 0.2% chance of exploitation in 30 days, percentile 12%
- public exploits
- 0
- none known
Summary
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.
Patch / fix
- librechat librechat 0.8.3
CISA SSVC
- Exploitation
- Proof of concept is public
- Automatable
- no
- Technical impact
- partial
- Assessed
- 7 mo ago
Exploit prediction
0.22% chance of exploitation in the next 30 days, higher than 12% of all scored CVEs (FIRST EPSS, 2026-11-08).
Exploits and checks
- github.com https://github.com/danny-avila/LibreChat/security/advisories/GHSA-w5r7-4f94-vp4c referenced PoC, tagged "exploit" by a source, unverified
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 8.5 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:N |
Affected products
- danny-avila LibreChat
Classification
- Weakness
-
- CWE-918 Server-Side Request Forgery
References
-
github.com
/danny-avila/LibreChat/security/advisories/GHSA-w5r7-4f94-vp4c
exploit, vendor-advisory
Sources
- CVE List CVE-2026-31943
- NVD CVE-2026-31943
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