Mednafen is an advanced NES, GB/GBC/GBA, TurboGrafx 16/CD, NGPC and Lynx emulator.
An unspecified vulnerability has been discovered in Mednafen when using network play.
A remote server could execute arbitrary code with the privileges of the process.
There is no known workaround at this time.
All Mednafen users should upgrade to the latest version:
# emerge --sync
# emerge --ask --oneshot --verbose ">=games-emulation/mednafen-0.8.13"