The bitsubstr function in backend/utils/adt/varbit.c in PostgreSQL 8.0.23, 8.1.11, and 8.3.8 allows remote authenticated users to cause a denial of service (daemon crash) or have unspecified other impact via vectors involving a negative integer in the third argument, as demonstrated by a SELECT statement that contains a call to the substring function for a bit string, related to an "overflow."
The postgresql-ocaml bindings 1.5.4, 1.7.0, and 1.12.1 for PostgreSQL libpq do not properly support the PQescapeStringConn function, which might allow remote attackers to leverage escaping issues involving multibyte character encodings.
The core server component in PostgreSQL 8.3 before 8.3.8 and 8.2 before 8.2.14, when using LDAP authentication with anonymous binds, allows remote attackers to bypass authentication via an empty password.
The core server component in PostgreSQL 8.4 before 8.4.1, 8.3 before 8.3.8, and 8.2 before 8.2.14 allows remote authenticated users to cause a denial of service (backend shutdown) by "re-LOAD-ing" libraries from a certain plugins directory.