CVE-2026-33250 in freeciv21
Summary
Freeciv21 is a free open source, turn-based, empire-building strategy game. Versions prior to 3.1.1 crash with a stack overflow when receiving specially-crafted packets. A remote attacker can use this to take down any public server. A malicious server can use this to crash the game on the player's machine. Authentication is not needed and, by default, logs do not contain any useful information. All users should upgrade to Freeciv21 version 3.1.1. Running the server behind a firewall can help mitigate the issue for non-public servers. For local games, Freeciv21 restricts connections to the current user and is therefore not affected.
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Responsible
GitHub_M
Reservation
03/18/2026
Disclosure
03/24/2026
Status
Confirmed
Entries
VulDB provides additional information and datapoints for this CVE:
| ID | Vulnerability | CWE | Exp | Cou | CVE |
|---|---|---|---|---|---|
| 352598 | longturn freeciv21 stack-based overflow | 121 | Not defined | Official fix | CVE-2026-33250 |