Perl-Compatible Regular Expression (PCRE) library before 6.7 allows context-dependent attackers to cause a denial of service (error or crash) via a regular expression that involves a "malformed POSIX character class", as demonstrated via an invalid character after a [[ sequence.

Perl-Compatible Regular Expression (PCRE) library before 7.0 does not properly calculate the amount of memory needed for a compiled regular expression pattern when the (1) -x or (2) -i UTF-8 options change within the pattern, which allows context-dependent attackers to cause a denial of service (PCRE or glibc crash) via crafted regular expressions.

Perl-Compatible Regular Expression (PCRE) library before 7.3 allows context-dependent attackers to cause a denial of service (crash) and possibly execute arbitrary code via regex patterns containing unmatched "\Q\E" sequences with orphan "\E" codes.

Multiple integer overflows in Perl-Compatible Regular Expression (PCRE) library before 7.3 allow context-dependent attackers to cause a denial of service (crash) or execute arbitrary code via unspecified escape (backslash) sequences.

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.

Perl-Compatible Regular Expression (PCRE) library before 7.0 does not properly calculate sizes for unspecified "multiple forms of character class", which triggers a buffer overflow that allows context-dependent attackers to cause a denial of service (crash) and possibly execute arbitrary code.

Perl-Compatible Regular Expression (PCRE) library before 7.3 reads past the end of the string when searching for unmatched brackets and parentheses, which allows context-dependent attackers to cause a denial of service (crash), possibly involving forward references.

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.

Integer overflow in pcre_compile.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.