The exit_notify function in kernel/exit.c in the Linux kernel before 2.6.30-rc1 does not restrict exit signals when the CAP_KILL capability is held, which allows local users to send an arbitrary signal to a process by running a program that modifies the exit_signal field and then uses an exec system call to launch a setuid application.
https://www.redhat.com/archives/fedora-package-announce/2009-May/msg01126.html
https://rhn.redhat.com/errata/RHSA-2009-1550.html
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A8295
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A11206
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A10919
https://bugzilla.redhat.com/show_bug.cgi?id=493771
http://www.vupen.com/english/advisories/2009/3316
http://www.vmware.com/security/advisories/VMSA-2009-0016.html
http://www.ubuntu.com/usn/usn-793-1
http://www.securitytracker.com/id?1022141
http://www.securityfocus.com/bid/34405
http://www.securityfocus.com/archive/1/512019/100/0/threaded
http://www.securityfocus.com/archive/1/507985/100/0/threaded
http://www.securityfocus.com/archive/1/503610/100/0/threaded
http://www.redhat.com/support/errata/RHSA-2009-1077.html
http://www.redhat.com/support/errata/RHSA-2009-1024.html
http://www.redhat.com/support/errata/RHSA-2009-0451.html
http://www.openwall.com/lists/oss-security/2009/04/17/3
http://www.openwall.com/lists/oss-security/2009/04/07/1
http://www.mandriva.com/security/advisories?name=MDVSA-2009:135
http://www.mandriva.com/security/advisories?name=MDVSA-2009:119
http://www.kernel.org/pub/linux/kernel/v2.6/testing/ChangeLog-2.6.30-rc1
http://www.debian.org/security/2009/dsa-1800
http://www.debian.org/security/2009/dsa-1794
http://www.debian.org/security/2009/dsa-1787
http://wiki.rpath.com/Advisories:rPSA-2009-0084
http://secunia.com/advisories/37471
http://secunia.com/advisories/35656
http://secunia.com/advisories/35394
http://secunia.com/advisories/35390
http://secunia.com/advisories/35387
http://secunia.com/advisories/35324
http://secunia.com/advisories/35226
http://secunia.com/advisories/35185
http://secunia.com/advisories/35160
http://secunia.com/advisories/35121
http://secunia.com/advisories/35120
http://secunia.com/advisories/35015
http://secunia.com/advisories/35011
http://secunia.com/advisories/34981
http://secunia.com/advisories/34917
http://rhn.redhat.com/errata/RHSA-2009-0473.html
http://patchwork.kernel.org/patch/16544/
http://marc.info/?l=linux-kernel&m=123560588713763&w=2
http://lists.opensuse.org/opensuse-security-announce/2009-06/msg00002.html
http://lists.opensuse.org/opensuse-security-announce/2009-06/msg00001.html
http://lists.opensuse.org/opensuse-security-announce/2009-06/msg00000.html
http://lists.opensuse.org/opensuse-security-announce/2009-05/msg00002.html