GNU Bison before 3.7.1 has a use-after-free in _obstack_free in lib/obstack.c (called from gram_lex) when a ” byte is encountered. NOTE: there is a risk only if Bison is used with untrusted input, and the observed bug happens to cause unsafe behavior with a specific compiler/architecture. The bug report was intended to show that a crash may occur in Bison itself, not that a crash may occur in code that is generated by Bison.
bison
CVE-2020-14150
GNU Bison before 3.5.4 allows attackers to cause a denial of service (application crash). NOTE: there is a risk only if Bison is used with untrusted input, and an observed bug happens to cause unsafe behavior with a specific compiler/architecture. The bug reports were intended to show that a crash may occur in Bison itself, not that a crash may occur in code that is generated by Bison.