The query planner in PostgreSQL before 8.0.11, 8.1 before 8.1.7, and 8.2 before 8.2.2 does not verify that a table is compatible with a "previously made query plan," which allows remote authenticated users to cause a denial of service (server crash) and possibly access database content via an "ALTER COLUMN TYPE" SQL statement, which can be leveraged to read arbitrary memory from the server.
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A11353
https://issues.rpath.com/browse/RPL-830
https://issues.rpath.com/browse/RPL-1025
https://exchange.xforce.ibmcloud.com/vulnerabilities/32191
http://www.vupen.com/english/advisories/2007/0774
http://www.vupen.com/english/advisories/2007/0478
http://www.ubuntu.com/usn/usn-417-2
http://www.trustix.org/errata/2007/0007
http://www.securityfocus.com/bid/22387
http://www.securityfocus.com/archive/1/459448/100/0/threaded
http://www.securityfocus.com/archive/1/459280/100/0/threaded
http://www.redhat.com/support/errata/RHSA-2007-0068.html
http://www.redhat.com/support/errata/RHSA-2007-0067.html
http://www.postgresql.org/support/security
http://www.novell.com/linux/security/advisories/2007_10_sr.html
http://www.mandriva.com/security/advisories?name=MDKSA-2007:037
http://support.avaya.com/elmodocs2/security/ASA-2007-117.htm
http://sunsolve.sun.com/search/document.do?assetkey=1-26-102825-1
http://securitytracker.com/id?1017597
http://security.gentoo.org/glsa/glsa-200703-15.xml
http://secunia.com/advisories/25220
http://secunia.com/advisories/24577
http://secunia.com/advisories/24513
http://secunia.com/advisories/24315
http://secunia.com/advisories/24151
http://secunia.com/advisories/24057
http://secunia.com/advisories/24050
http://secunia.com/advisories/24042
http://secunia.com/advisories/24033
http://secunia.com/advisories/24028
http://lists.rpath.com/pipermail/security-announce/2007-February/000141.html