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

> Authenticated users can bypass SSRF protections to access internal network resources and cloud metadata services.

- **Severity:** High 8.5 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 27 Mar 2026
- **Updated:** 31 Mar 2026
- **Also known as:** GHSA-w5r7-4f94-vp4c

## What is CVE-2026-31943?

CVE-2026-31943 is a high-severity server-side request forgery vulnerability in Librechat Librechat, published on 27 Mar 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official 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.

Weakness: CWE-918 (Server-Side Request Forgery)

## Which versions are affected by CVE-2026-31943?

It affects 1 product.


Products: Librechat Librechat.

## How do I fix CVE-2026-31943?

No fix has been published for CVE-2026-31943 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-31943 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-31943 exists.

## Other vulnerabilities in Librechat Librechat

- [CVE-2026-32625](https://insights.sbomify.com/CVE-2026-32625/): LibreChat Exfiltrates Server Secrets via MCP Server URL Injection (critical 9.6)
- [CVE-2024-11167](https://insights.sbomify.com/CVE-2024-11167/): Improper Access Control in danny-avila/librechat (critical 9.4)
- [CVE-2026-22252](https://insights.sbomify.com/CVE-2026-22252/): LibreChat MCP Stdio Remote Command Execution (critical 9.1)
- [CVE-2025-69222](https://insights.sbomify.com/CVE-2025-69222/): LibreChat is vulnerable to Server-Side Request Forgery due to missing restrictions (critical 9.1)
- [CVE-2024-41704](https://insights.sbomify.com/CVE-2024-41704/): Path traversal in n/a (critical 9.1)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-31943 and fix it if it is affected.

What it is: CVE-2026-31943 is a high-severity server-side request forgery vulnerability in Librechat Librechat, published on 27 Mar 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-31943 exists.

Affected product: Librechat Librechat. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-31943/ (Markdown: https://insights.sbomify.com/CVE-2026-31943/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-31943
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-31943
- OSV: https://osv.dev/vulnerability/CVE-2026-31943

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-31943/
Summaries are generated and may contain mistakes; the official description above is the record.