# CVE-2026-33250: freeciv: Freeciv21 is a free open source, turn-based, empire-building strategy game CVE-2026-33250 is fixed in 10 products on 1 platform, first by DSA-6173-1, released March 21, 2026. It is not reported as exploited. Patch Radar priority: High. - Web page: https://patchblox.com/security/cve/CVE-2026-33250 - Priority: High - CVSS: 7.5 (Medium) - EPSS: 0.0085 - CISA KEV: not listed - Exploited (vendor report): no - Publicly disclosed: no - Published: Mar 21, 2026 ## Description 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. ## Where it's fixed | Platform | Product | Fixed in | Fix | Released | |---|---|---|---|---| | Linux | freeciv Debian 12.15 (bookworm) | 3.0.6-1+deb12u1 | [DSA-6173-1](https://patchblox.com/security/data/fix/linux/dsa-6173-1.md) | Mar 21, 2026 | | Linux | freeciv Debian 13.5 (trixie) | 3.1.4+ds-2+deb13u1 | [DSA-6173-1](https://patchblox.com/security/data/fix/linux/dsa-6173-1.md) | Mar 21, 2026 | | Linux | freeciv Debian 14 | 3.2.4+ds-1 | [DEBIAN-CVE-2026-33250](https://patchblox.com/security/data/fix/linux/debian-cve-2026-33250.md) | Mar 24, 2026 | | Linux | freeciv Ubuntu 18.04.6 LTS (bionic) | 2.5.10-1ubuntu0.1~esm1 | [freeciv 2.5.10-1ubuntu0.1~esm1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-freeciv-2.5.10-1ubuntu0.1-esm1.md) | Mar 23, 2026 | | Linux | freeciv Ubuntu 20.04 LTS (focal) | 2.6.2-1ubuntu0.1~esm1 | [freeciv 2.6.2-1ubuntu0.1~esm1](https://patchblox.com/security/data/fix/linux/ubuntu-focal-freeciv-2.6.2-1ubuntu0.1-esm1.md) | Mar 23, 2026 | | Linux | freeciv Ubuntu 22.04.1 LTS (jammy) | 2.6.6-1ubuntu0.1~esm1 | [freeciv 2.6.6-1ubuntu0.1~esm1](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-freeciv-2.6.6-1ubuntu0.1-esm1.md) | Mar 23, 2026 | | Linux | freeciv Ubuntu 24.04.5 LTS (noble) | 3.1.0+ds-1ubuntu0.1~esm1 | [freeciv 3.1.0+ds-1ubuntu0.1~esm1](https://patchblox.com/security/data/fix/linux/ubuntu-noble-freeciv-3.1.0-ds-1ubuntu0.1-esm1.md) | Mar 23, 2026 | | Linux | freeciv opensuse-leap 16.0 | 3.2.4-bp160.1.1 | [OPENSUSE-SU-2026:20423-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-20423-1.md) | Mar 23, 2026 | | Linux | freeciv-client-extras Ubuntu 18.04.6 LTS (bionic) | 2.5.10-1ubuntu0.1~esm1 | [freeciv-client-extras 2.5.10-1ubuntu0.1~esm1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-freeciv-client-extras-2.5.10-1ubuntu0.1-esm1.md) | Mar 23, 2026 | | Linux | freeciv-client-extras Ubuntu 20.04 LTS (focal) | 2.6.2-1ubuntu0.1~esm1 | [freeciv-client-extras 2.6.2-1ubuntu0.1~esm1](https://patchblox.com/security/data/fix/linux/ubuntu-focal-freeciv-client-extras-2.6.2-1ubuntu0.1-esm1.md) | Mar 23, 2026 | | Linux | freeciv-client-extras Ubuntu 22.04.1 LTS (jammy) | 2.6.6-1ubuntu0.1~esm1 | [freeciv-client-extras 2.6.6-1ubuntu0.1~esm1](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-freeciv-client-extras-2.6.6-1ubuntu0.1-esm1.md) | Mar 23, 2026 | | Linux | freeciv-client-extras Ubuntu 24.04.5 LTS (noble) | 3.1.0+ds-1ubuntu0.1~esm1 | [freeciv-client-extras 3.1.0+ds-1ubuntu0.1~esm1](https://patchblox.com/security/data/fix/linux/ubuntu-noble-freeciv-client-extras-3.1.0-ds-1ubuntu0.1-esm1.md) | Mar 23, 2026 | | Linux | freeciv-client-gtk Ubuntu 18.04.6 LTS (bionic) | 2.5.10-1ubuntu0.1~esm1 | [freeciv-client-gtk 2.5.10-1ubuntu0.1~esm1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-freeciv-client-gtk-2.5.10-1ubuntu0.1-esm1.md) | Mar 23, 2026 | | Linux | freeciv-client-gtk Ubuntu 20.04 LTS (focal) | 2.6.2-1ubuntu0.1~esm1 | [freeciv-client-gtk 2.6.2-1ubuntu0.1~esm1](https://patchblox.com/security/data/fix/linux/ubuntu-focal-freeciv-client-gtk-2.6.2-1ubuntu0.1-esm1.md) | Mar 23, 2026 | | Linux | freeciv-client-gtk Ubuntu 22.04.1 LTS (jammy) | 2.6.6-1ubuntu0.1~esm1 | [freeciv-client-gtk 2.6.6-1ubuntu0.1~esm1](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-freeciv-client-gtk-2.6.6-1ubuntu0.1-esm1.md) | Mar 23, 2026 | | Linux | freeciv-client-gtk3 Ubuntu 18.04.6 LTS (bionic) | 2.5.10-1ubuntu0.1~esm1 | [freeciv-client-gtk3 2.5.10-1ubuntu0.1~esm1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-freeciv-client-gtk3-2.5.10-1ubuntu0.1-esm1.md) | Mar 23, 2026 | | Linux | freeciv-client-gtk3 Ubuntu 20.04 LTS (focal) | 2.6.2-1ubuntu0.1~esm1 | [freeciv-client-gtk3 2.6.2-1ubuntu0.1~esm1](https://patchblox.com/security/data/fix/linux/ubuntu-focal-freeciv-client-gtk3-2.6.2-1ubuntu0.1-esm1.md) | Mar 23, 2026 | | Linux | freeciv-client-gtk3 Ubuntu 22.04.1 LTS (jammy) | 2.6.6-1ubuntu0.1~esm1 | [freeciv-client-gtk3 2.6.6-1ubuntu0.1~esm1](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-freeciv-client-gtk3-2.6.6-1ubuntu0.1-esm1.md) | Mar 23, 2026 | | Linux | freeciv-client-gtk3 Ubuntu 24.04.5 LTS (noble) | 3.1.0+ds-1ubuntu0.1~esm1 | [freeciv-client-gtk3 3.1.0+ds-1ubuntu0.1~esm1](https://patchblox.com/security/data/fix/linux/ubuntu-noble-freeciv-client-gtk3-3.1.0-ds-1ubuntu0.1-esm1.md) | Mar 23, 2026 | | Linux | freeciv-client-qt Ubuntu 18.04.6 LTS (bionic) | 2.5.10-1ubuntu0.1~esm1 | [freeciv-client-qt 2.5.10-1ubuntu0.1~esm1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-freeciv-client-qt-2.5.10-1ubuntu0.1-esm1.md) | Mar 23, 2026 | | Linux | freeciv-client-qt Ubuntu 20.04 LTS (focal) | 2.6.2-1ubuntu0.1~esm1 | [freeciv-client-qt 2.6.2-1ubuntu0.1~esm1](https://patchblox.com/security/data/fix/linux/ubuntu-focal-freeciv-client-qt-2.6.2-1ubuntu0.1-esm1.md) | Mar 23, 2026 | | Linux | freeciv-client-qt Ubuntu 22.04.1 LTS (jammy) | 2.6.6-1ubuntu0.1~esm1 | [freeciv-client-qt 2.6.6-1ubuntu0.1~esm1](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-freeciv-client-qt-2.6.6-1ubuntu0.1-esm1.md) | Mar 23, 2026 | | Linux | freeciv-client-qt Ubuntu 24.04.5 LTS (noble) | 3.1.0+ds-1ubuntu0.1~esm1 | [freeciv-client-qt 3.1.0+ds-1ubuntu0.1~esm1](https://patchblox.com/security/data/fix/linux/ubuntu-noble-freeciv-client-qt-3.1.0-ds-1ubuntu0.1-esm1.md) | Mar 23, 2026 | | Linux | freeciv-client-sdl Ubuntu 18.04.6 LTS (bionic) | 2.5.10-1ubuntu0.1~esm1 | [freeciv-client-sdl 2.5.10-1ubuntu0.1~esm1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-freeciv-client-sdl-2.5.10-1ubuntu0.1-esm1.md) | Mar 23, 2026 | | Linux | freeciv-client-sdl Ubuntu 20.04 LTS (focal) | 2.6.2-1ubuntu0.1~esm1 | [freeciv-client-sdl 2.6.2-1ubuntu0.1~esm1](https://patchblox.com/security/data/fix/linux/ubuntu-focal-freeciv-client-sdl-2.6.2-1ubuntu0.1-esm1.md) | Mar 23, 2026 | | Linux | freeciv-client-sdl Ubuntu 22.04.1 LTS (jammy) | 2.6.6-1ubuntu0.1~esm1 | [freeciv-client-sdl 2.6.6-1ubuntu0.1~esm1](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-freeciv-client-sdl-2.6.6-1ubuntu0.1-esm1.md) | Mar 23, 2026 | | Linux | freeciv-client-sdl Ubuntu 24.04.5 LTS (noble) | 3.1.0+ds-1ubuntu0.1~esm1 | [freeciv-client-sdl 3.1.0+ds-1ubuntu0.1~esm1](https://patchblox.com/security/data/fix/linux/ubuntu-noble-freeciv-client-sdl-3.1.0-ds-1ubuntu0.1-esm1.md) | Mar 23, 2026 | | Linux | freeciv-data Ubuntu 18.04.6 LTS (bionic) | 2.5.10-1ubuntu0.1~esm1 | [freeciv-data 2.5.10-1ubuntu0.1~esm1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-freeciv-data-2.5.10-1ubuntu0.1-esm1.md) | Mar 23, 2026 | | Linux | freeciv-data Ubuntu 20.04 LTS (focal) | 2.6.2-1ubuntu0.1~esm1 | [freeciv-data 2.6.2-1ubuntu0.1~esm1](https://patchblox.com/security/data/fix/linux/ubuntu-focal-freeciv-data-2.6.2-1ubuntu0.1-esm1.md) | Mar 23, 2026 | | Linux | freeciv-data Ubuntu 22.04.1 LTS (jammy) | 2.6.6-1ubuntu0.1~esm1 | [freeciv-data 2.6.6-1ubuntu0.1~esm1](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-freeciv-data-2.6.6-1ubuntu0.1-esm1.md) | Mar 23, 2026 | | Linux | freeciv-data Ubuntu 24.04.5 LTS (noble) | 3.1.0+ds-1ubuntu0.1~esm1 | [freeciv-data 3.1.0+ds-1ubuntu0.1~esm1](https://patchblox.com/security/data/fix/linux/ubuntu-noble-freeciv-data-3.1.0-ds-1ubuntu0.1-esm1.md) | Mar 23, 2026 | | Linux | freeciv-ruleset-tools Ubuntu 24.04.5 LTS (noble) | 3.1.0+ds-1ubuntu0.1~esm1 | [freeciv-ruleset-tools 3.1.0+ds-1ubuntu0.1~esm1](https://patchblox.com/security/data/fix/linux/ubuntu-noble-freeciv-ruleset-tools-3.1.0-ds-1ubuntu0.1-esm1.md) | Mar 23, 2026 | | Linux | freeciv-server Ubuntu 18.04.6 LTS (bionic) | 2.5.10-1ubuntu0.1~esm1 | [freeciv-server 2.5.10-1ubuntu0.1~esm1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-freeciv-server-2.5.10-1ubuntu0.1-esm1.md) | Mar 23, 2026 | | Linux | freeciv-server Ubuntu 20.04 LTS (focal) | 2.6.2-1ubuntu0.1~esm1 | [freeciv-server 2.6.2-1ubuntu0.1~esm1](https://patchblox.com/security/data/fix/linux/ubuntu-focal-freeciv-server-2.6.2-1ubuntu0.1-esm1.md) | Mar 23, 2026 | | Linux | freeciv-server Ubuntu 22.04.1 LTS (jammy) | 2.6.6-1ubuntu0.1~esm1 | [freeciv-server 2.6.6-1ubuntu0.1~esm1](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-freeciv-server-2.6.6-1ubuntu0.1-esm1.md) | Mar 23, 2026 | | Linux | freeciv-server Ubuntu 24.04.5 LTS (noble) | 3.1.0+ds-1ubuntu0.1~esm1 | [freeciv-server 3.1.0+ds-1ubuntu0.1~esm1](https://patchblox.com/security/data/fix/linux/ubuntu-noble-freeciv-server-3.1.0-ds-1ubuntu0.1-esm1.md) | Mar 23, 2026 | | Linux | freeciv-sound-standard Ubuntu 18.04.6 LTS (bionic) | 2.5.10-1ubuntu0.1~esm1 | [freeciv-sound-standard 2.5.10-1ubuntu0.1~esm1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-freeciv-sound-standard-2.5.10-1ubuntu0.1-esm1.md) | Mar 23, 2026 | | Linux | freeciv-sound-standard Ubuntu 20.04 LTS (focal) | 2.6.2-1ubuntu0.1~esm1 | [freeciv-sound-standard 2.6.2-1ubuntu0.1~esm1](https://patchblox.com/security/data/fix/linux/ubuntu-focal-freeciv-sound-standard-2.6.2-1ubuntu0.1-esm1.md) | Mar 23, 2026 | | Linux | freeciv-sound-standard Ubuntu 22.04.1 LTS (jammy) | 2.6.6-1ubuntu0.1~esm1 | [freeciv-sound-standard 2.6.6-1ubuntu0.1~esm1](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-freeciv-sound-standard-2.6.6-1ubuntu0.1-esm1.md) | Mar 23, 2026 | --- Data as of 2026-11-08T19:12:23Z UTC. 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