# CVE-2023-34243: Windows user name disclosure in TGstation

> Attackers can discover Windows usernames by brute-forcing the login endpoint due to distinct responses for valid logons.

- **Severity:** Medium 5.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 8 Jun 2023
- **Updated:** 6 Jan 2025
- **Also known as:** GHSA-w3jx-4x93-76ph

## What is CVE-2023-34243?

CVE-2023-34243 is a medium-severity vulnerability in tgstation-server, published on 8 Jun 2023. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

TGstation is a toolset to manage production BYOND servers. In affected versions if a Windows user was registered in tgstation-server (TGS), an attacker could discover their username by brute-forcing the login endpoint with an invalid password. When a valid Windows logon was found, a distinct response would be generated. This issue has been addressed in version 5.12.5. Users are advised to upgrade. Users unable to upgrade may be mitigated by rate-limiting API calls with software that sits in front of TGS in the HTTP pipeline such as fail2ban.

Weakness: CWE-307 (Improper Restriction of Excessive Authentication Attempts), CWE-200 (Exposure of Sensitive Information to an Unauthorized Actor)

## Which versions are affected by CVE-2023-34243?

It affects 1 product.


Products: Tgstation13 Tgstation-Server.

## How do I fix CVE-2023-34243?

No fix has been published for CVE-2023-34243 yet. Limit exposure of the affected software until one is available.

## Is CVE-2023-34243 being exploited?

There is no known exploitation of CVE-2023-34243 in the wild and no public exploit code.

## Other vulnerabilities in tgstation-server

- [CVE-2018-17107](https://insights.sbomify.com/CVE-2018-17107/): tgstation-server cached user logins in legacy server (critical 9.8)
- [CVE-2025-21611](https://insights.sbomify.com/CVE-2025-21611/): tgstation-server's role authorization incorrectly OR'd with user's enabled status (high 8.8)
- [CVE-2024-41799](https://insights.sbomify.com/CVE-2024-41799/): tgstation-server's DreamMaker environment files outside the deployment directory can be compiled and ran by insufficiently permissioned users (high 8.4)
- [CVE-2023-32687](https://insights.sbomify.com/CVE-2023-32687/): Insufficiently Protected ChatBot Credentials in tgstation-server (high 7.7)
- [CVE-2020-16136](https://insights.sbomify.com/CVE-2020-16136/): Path traversal in n/a (high 7.7)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2023-34243 and fix it if it is affected.

What it is: CVE-2023-34243 is a medium-severity vulnerability in tgstation-server, published on 8 Jun 2023. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2023-34243 in the wild and no public exploit code.

Affected product: tgstation-server. 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-2023-34243/ (Markdown: https://insights.sbomify.com/CVE-2023-34243/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-34243
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-34243
- OSV: https://osv.dev/vulnerability/CVE-2023-34243

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-34243/
Summaries are generated and may contain mistakes; the official description above is the record.