In ioquake3 before 2017-03-14, the auto-downloading feature has insufficient content restrictions. This also affects Quake III Arena, OpenArena, OpenJK, iortcw, and other id Tech 3 (aka Quake 3 engine) forks. A malicious auto-downloaded file can trigger loading of crafted auto-downloaded files as native code DLLs. A malicious auto-downloaded file can contain configuration defaults that override the user's. Executable bytecode in a malicious auto-downloaded file can set configuration variables to values that will result in unwanted native code DLLs being loaded, resulting in sandbox escape.
https://ioquake3.org/2017/03/13/important-security-update-please-update-ioquake3-immediately/
https://github.com/iortcw/iortcw/commit/b6ff2bcb1e4e6976d61e316175c6d7c99860fe20
https://github.com/iortcw/iortcw/commit/b248763e4878ef12d5835ece6600be8334f67da1
https://github.com/iortcw/iortcw/commit/11a83410153756ae350a82ed41b08d128ff7f998
https://github.com/ioquake/ioq3/commit/f61fe5f6a0419ef4a88d46a128052f2e8352e85d
https://github.com/ioquake/ioq3/commit/b173ac05993f634a42be3d3535e1b158de0c3372
https://github.com/ioquake/ioq3/commit/376267d534476a875d8b9228149c4ee18b74a4fd
https://github.com/JACoders/OpenJK/commit/8956a35e7b91c4a0dd1fa6db1d28c7f0efbab2d7