As promised, id Software has released a beta version 1.27h patch for Quake III Arena for download from their ftp server and mirrored on cdrom.com (816 KB). This patch requires the 1.27g point release and addresses the previously mentioned multiplayer exploit bug, the mouse sensitivity, and a few other issues as listed in the README:

Fixes and Additions
- Fixed James model bug
- CD Key read correctly when starting from Q3A vs TA shortcuts
- Handicap exploit fixed
- Bot routing bug fixed
- Potential 20 FPS increase for some clients :-)
- Sensitivity is back how it was