Red Hat: RHSA-2009:1108-01 Moderate: httpd Update Security Advisory

The Apache HTTP Server is a popular Web server. The httpd package shipped with Red Hat Enterprise Linux 3 contains an embedded copy of the Apache Portable Runtime (APR) utility library, a free library of C data structures and routines, which includes interfaces to support XML parsing, LDAP connections, database interfaces, URI parsing, and more.
An off-by-one overflow flaw was found in the way apr-util processed a variable list of arguments. An attacker could provide a specially-crafted string as input for the formatted output conversion routine, which could, on big-endian platforms, potentially lead to the disclosure of sensitive information or a denial of service (application crash). (CVE-2009-1956)
Note: The CVE-2009-1956 flaw only affects big-endian platforms, such as the IBM S/390 and PowerPC. It does not affect users using the httpd package on little-endian platforms, due to their different organization of byte ordering used to represent particular data.
A denial of service flaw was found in the apr-util Extensible Markup Language (XML) parser. A remote attacker could create a specially-crafted XML document that would cause excessive memory consumption when processed by the XML decoding engine. (CVE-2009-1955)
A heap-based underwrite flaw was found in the way apr-util created compiled forms of particular search patterns. An attacker could formulate a specially-crafted search keyword, that would overwrite arbitrary heap memory locations when processed by the pattern preparation engine. (CVE-2009-0023)
All httpd users should upgrade to these updated packages, which contain backported patches to correct these issues. After installing the updated packages, the httpd daemon must be restarted for the update to take effect.