Freeciv before 2.6.7 and before 3.0.3 is prone to a buffer overflow vulnerability in the Modpack Installer utility's handling of the modpack URL.
Freeciv before 2.3.3 allows remote attackers to cause a denial of service via a crafted packet.
freeciv 2.2 before 2.2.1 and 2.3 before 2.3.0 allows attackers to read arbitrary files or execute arbitrary commands via a scenario that contains Lua functionality, related to the (1) os, (2) io, (3) package, (4) dofile, (5) loadfile, (6) loadlib, (7) module, and (8) require modules or functions.