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.

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 7.3 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.

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.