Integer overflow in pcrecompile.c in Perl Compatible Regular Expressions (PCRE) before 6.2, as used in multiple products such as Python, Ethereal, and PHP, allows attackers to execute arbitrary code via quantifier values in regular expressions, which leads to a heap-based buffer overflow.

Heap-based buffer overflow in Perl-Compatible Regular Expression (PCRE) library before 7.3 allows context-dependent attackers to execute arbitrary code via a singleton Unicode sequence in a character class in a regex pattern, which is incorrectly optimized.

Perl-Compatible Regular Expression (PCRE) library before 7.3 does not properly compute the length of (1) a \p sequence, (2) a \P sequence, or (3) a \P{x} sequence, which allows context-dependent attackers to cause a denial of service (infinite loop or crash) or execute arbitrary code.

CVE-2006-7224 initially described several integer overflows in pcre, all described here: http://scary.beasts.org/security/CESA-2007-006.html

This id should be used to describe issue #2 in that advisory:

2) Uncharacterized crash researching item #1 above: Demo:

(?P<0>)(?P<1>)...fill in this sequence...(?P<3999>)

This does not trigger the integer overflow present in #1 above, but still crashes with a serious-looking memory error of some kind - possibly a buffer overflow.