Integer overflow in the regcomp implementation in the Henry Spencer BSD regex library (aka rxspencer) alpha3.8.g5 on 32-bit platforms, as used in NetBSD through 6.1.5 and other products, might allow context-dependent attackers to execute arbitrary code via a large regular expression that leads to a heap-based buffer overflow.
Integer Overflow or Wraparound The product performs a calculation that can
produce an integer overflow or wraparound when the logic
assumes that the resulting value will always be larger than
the original value. This occurs when an integer value is
incremented to a value that is too large to store in the
associated representation. When this occurs, the value may
become a very small or negative number.