{"id":"UBUNTU-CVE-2026-33250","details":"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.","modified":"2026-09-14T22:00:28.276977333Z","published":"2026-03-24T00:16:00Z","related":["USN-8754-1"],"upstream":["CVE-2026-33250"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-33250"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2026-33250"},{"type":"REPORT","url":"https://redmine.freeciv.org/issues/1955"},{"type":"REPORT","url":"https://github.com/longturn/freeciv21/commit/ad8e18ca22595529599782b2984bf44df8d69ed6"},{"type":"REPORT","url":"https://github.com/longturn/freeciv21/releases/tag/v3.1.1"},{"type":"REPORT","url":"https://github.com/longturn/freeciv21/security/advisories/GHSA-f76g-6w3f-f6r3"},{"type":"ADVISORY","url":"https://ubuntu.com/security/notices/USN-8754-1"}],"affected":[{"package":{"name":"freeciv","ecosystem":"Ubuntu:Pro:16.04:LTS","purl":"pkg:deb/ubuntu/freeciv?arch=source&distro=esm-apps-legacy%2Fxenial"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.5.3-1ubuntu0.1~esm1"}]}],"versions":["2.5.1-1","2.5.2-1","2.5.3-1"],"ecosystem_specific":{"binaries":[{"binary_name":"freeciv","binary_version":"2.5.3-1ubuntu0.1~esm1"},{"binary_name":"freeciv-client-extras","binary_version":"2.5.3-1ubuntu0.1~esm1"},{"binary_name":"freeciv-client-gtk","binary_version":"2.5.3-1ubuntu0.1~esm1"},{"binary_name":"freeciv-client-qt","binary_version":"2.5.3-1ubuntu0.1~esm1"},{"binary_name":"freeciv-client-sdl","binary_version":"2.5.3-1ubuntu0.1~esm1"},{"binary_version":"2.5.3-1ubuntu0.1~esm1","binary_name":"freeciv-data"},{"binary_name":"freeciv-server","binary_version":"2.5.3-1ubuntu0.1~esm1"},{"binary_name":"freeciv-sound-standard","binary_version":"2.5.3-1ubuntu0.1~esm1"}],"availability":"Available with Ubuntu Pro with Legacy support add-on: https://ubuntu.com/pro"},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-33250.json"}},{"package":{"name":"freeciv","ecosystem":"Ubuntu:Pro:18.04:LTS","purl":"pkg:deb/ubuntu/freeciv?arch=source&distro=esm-apps%2Fbionic"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.5.10-1ubuntu0.1~esm1"}]}],"versions":["2.5.9-1","2.5.10-1"],"ecosystem_specific":{"binaries":[{"binary_version":"2.5.10-1ubuntu0.1~esm1","binary_name":"freeciv"},{"binary_name":"freeciv-client-extras","binary_version":"2.5.10-1ubuntu0.1~esm1"},{"binary_version":"2.5.10-1ubuntu0.1~esm1","binary_name":"freeciv-client-gtk"},{"binary_version":"2.5.10-1ubuntu0.1~esm1","binary_name":"freeciv-client-gtk3"},{"binary_name":"freeciv-client-qt","binary_version":"2.5.10-1ubuntu0.1~esm1"},{"binary_version":"2.5.10-1ubuntu0.1~esm1","binary_name":"freeciv-client-sdl"},{"binary_name":"freeciv-data","binary_version":"2.5.10-1ubuntu0.1~esm1"},{"binary_name":"freeciv-server","binary_version":"2.5.10-1ubuntu0.1~esm1"},{"binary_version":"2.5.10-1ubuntu0.1~esm1","binary_name":"freeciv-sound-standard"}],"availability":"Available with Ubuntu Pro: https://ubuntu.com/pro"},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-33250.json"}},{"package":{"name":"freeciv","ecosystem":"Ubuntu:Pro:20.04:LTS","purl":"pkg:deb/ubuntu/freeciv?arch=source&distro=esm-apps%2Ffocal"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.6.2-1ubuntu0.1~esm1"}]}],"versions":["2.6.0-3","2.6.0-4","2.6.1-1","2.6.2-1"],"ecosystem_specific":{"binaries":[{"binary_name":"freeciv","binary_version":"2.6.2-1ubuntu0.1~esm1"},{"binary_name":"freeciv-client-extras","binary_version":"2.6.2-1ubuntu0.1~esm1"},{"binary_version":"2.6.2-1ubuntu0.1~esm1","binary_name":"freeciv-client-gtk"},{"binary_name":"freeciv-client-gtk3","binary_version":"2.6.2-1ubuntu0.1~esm1"},{"binary_name":"freeciv-client-qt","binary_version":"2.6.2-1ubuntu0.1~esm1"},{"binary_name":"freeciv-client-sdl","binary_version":"2.6.2-1ubuntu0.1~esm1"},{"binary_name":"freeciv-data","binary_version":"2.6.2-1ubuntu0.1~esm1"},{"binary_name":"freeciv-server","binary_version":"2.6.2-1ubuntu0.1~esm1"},{"binary_version":"2.6.2-1ubuntu0.1~esm1","binary_name":"freeciv-sound-standard"}],"availability":"Available with Ubuntu Pro: https://ubuntu.com/pro"},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-33250.json"}},{"package":{"name":"freeciv","ecosystem":"Ubuntu:Pro:22.04:LTS","purl":"pkg:deb/ubuntu/freeciv?arch=source&distro=esm-apps%2Fjammy"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.6.6-1ubuntu0.1~esm1"}]}],"versions":["2.6.3-1","2.6.5-1","2.6.6-1"],"ecosystem_specific":{"binaries":[{"binary_version":"2.6.6-1ubuntu0.1~esm1","binary_name":"freeciv"},{"binary_name":"freeciv-client-extras","binary_version":"2.6.6-1ubuntu0.1~esm1"},{"binary_name":"freeciv-client-gtk","binary_version":"2.6.6-1ubuntu0.1~esm1"},{"binary_name":"freeciv-client-gtk3","binary_version":"2.6.6-1ubuntu0.1~esm1"},{"binary_version":"2.6.6-1ubuntu0.1~esm1","binary_name":"freeciv-client-qt"},{"binary_version":"2.6.6-1ubuntu0.1~esm1","binary_name":"freeciv-client-sdl"},{"binary_name":"freeciv-data","binary_version":"2.6.6-1ubuntu0.1~esm1"},{"binary_version":"2.6.6-1ubuntu0.1~esm1","binary_name":"freeciv-server"},{"binary_name":"freeciv-sound-standard","binary_version":"2.6.6-1ubuntu0.1~esm1"}],"availability":"Available with Ubuntu Pro: https://ubuntu.com/pro"},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-33250.json"}},{"package":{"name":"freeciv","ecosystem":"Ubuntu:Pro:24.04:LTS","purl":"pkg:deb/ubuntu/freeciv?arch=source&distro=esm-apps%2Fnoble"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"3.1.0+ds-1ubuntu0.1~esm1"}]}],"versions":["3.0.8-1","3.0.8-2","3.0.8-2build1","3.1.0+ds-1build3","3.1.0+ds-1build4","3.1.0+ds-1build5"],"ecosystem_specific":{"binaries":[{"binary_version":"3.1.0+ds-1ubuntu0.1~esm1","binary_name":"freeciv"},{"binary_name":"freeciv-client-extras","binary_version":"3.1.0+ds-1ubuntu0.1~esm1"},{"binary_version":"3.1.0+ds-1ubuntu0.1~esm1","binary_name":"freeciv-client-gtk3"},{"binary_version":"3.1.0+ds-1ubuntu0.1~esm1","binary_name":"freeciv-client-qt"},{"binary_version":"3.1.0+ds-1ubuntu0.1~esm1","binary_name":"freeciv-client-sdl"},{"binary_version":"3.1.0+ds-1ubuntu0.1~esm1","binary_name":"freeciv-data"},{"binary_version":"3.1.0+ds-1ubuntu0.1~esm1","binary_name":"freeciv-ruleset-tools"},{"binary_version":"3.1.0+ds-1ubuntu0.1~esm1","binary_name":"freeciv-server"}],"availability":"Available with Ubuntu Pro: https://ubuntu.com/pro"},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-33250.json"}},{"package":{"name":"freeciv","ecosystem":"Ubuntu:25.10","purl":"pkg:deb/ubuntu/freeciv?arch=source&distro=questing"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["3.1.4+ds-2","3.2.0+ds-1"],"ecosystem_specific":{"binaries":[{"binary_version":"3.2.0+ds-1","binary_name":"freeciv"},{"binary_version":"3.2.0+ds-1","binary_name":"freeciv-client-extras"},{"binary_name":"freeciv-client-gtk3","binary_version":"3.2.0+ds-1"},{"binary_version":"3.2.0+ds-1","binary_name":"freeciv-client-gtk4"},{"binary_name":"freeciv-client-qt","binary_version":"3.2.0+ds-1"},{"binary_name":"freeciv-client-sdl","binary_version":"3.2.0+ds-1"},{"binary_version":"3.2.0+ds-1","binary_name":"freeciv-data"},{"binary_name":"freeciv-ruleset-tools","binary_version":"3.2.0+ds-1"},{"binary_name":"freeciv-server","binary_version":"3.2.0+ds-1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-33250.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"},{"type":"Ubuntu","score":"medium"}]}