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

Severity: medium (CVSS 5.3 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.5% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2023-06-08 · updated 2026-06-17
Weakness: CWE-200

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.

Affected products

tgstation-server: from 4.0.0.0 before 5.12.5 — fixed in 5.12.5

How to fix

Upgrade to a fixed version: tgstation-server 5.12.5. Check the vendor advisory for mitigations.

References

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