protocol.c in the Apache HTTP Server 2.2.x through 2.2.21 does not properly restrict header information during construction of Bad Request (aka 400) error documents, which allows remote attackers to obtain the values of HTTPOnly cookies via vectors involving a (1) long or (2) malformed header in conjunction with crafted web script.
https://bugzilla.redhat.com/show_bug.cgi?id=785069
http://www.securityfocus.com/bid/51706
http://www.oracle.com/technetwork/topics/security/cpujul2012-392727.html
http://www.oracle.com/technetwork/topics/security/cpujan2015-1972971.html
http://www.debian.org/security/2012/dsa-2405
http://svn.apache.org/viewvc?view=revision&revision=1235454
http://support.apple.com/kb/HT5501
http://secunia.com/advisories/48551
http://rhn.redhat.com/errata/RHSA-2012-0543.html
http://rhn.redhat.com/errata/RHSA-2012-0542.html
http://rhn.redhat.com/errata/RHSA-2012-0128.html
http://marc.info/?l=bugtraq&m=136441204617335&w=2
http://marc.info/?l=bugtraq&m=133951357207000&w=2
http://marc.info/?l=bugtraq&m=133494237717847&w=2
http://marc.info/?l=bugtraq&m=133294460209056&w=2
http://lists.opensuse.org/opensuse-security-announce/2012-03/msg00002.html
http://lists.opensuse.org/opensuse-security-announce/2012-02/msg00026.html