GNU Chess 6.2.7 allows attackers to execute arbitrary code via crafted PGN (Portable Game Notation) data. This is related to a buffer overflow in the use of a .tmp.epd temporary file in the cmd_pgnload and cmd_pgnreplay functions in frontend/cmd.cc.
https://security.gentoo.org/glsa/202107-28
https://lists.gnu.org/archive/html/bug-gnu-chess/2021-04/msg00001.html
https://lists.gnu.org/archive/html/bug-gnu-chess/2021-04/msg00000.html