The do_splice_from function in fs/splice.c in the Linux kernel before 2.6.27 does not reject file descriptors that have the O_APPEND flag set, which allows local users to bypass append mode and make arbitrary changes to other locations in the file.
https://www.redhat.com/archives/fedora-package-announce/2008-October/msg00693.html
https://www.redhat.com/archives/fedora-package-announce/2008-October/msg00689.html
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A11142
https://exchange.xforce.ibmcloud.com/vulnerabilities/45954
https://bugzilla.redhat.com/show_bug.cgi?id=466707
http://www.ubuntu.com/usn/usn-679-1
http://www.securityfocus.com/bid/31903
http://www.redhat.com/support/errata/RHSA-2009-0009.html
http://www.redhat.com/support/errata/RHSA-2008-1017.html
http://www.openwall.com/lists/oss-security/2008/10/14/5
http://www.openwall.com/lists/oss-security/2008/10/13/1
http://www.mandriva.com/security/advisories?name=MDVSA-2008:224
http://www.kernel.org/pub/linux/kernel/v2.6/ChangeLog-2.6.27
http://www.debian.org/security/2008/dsa-1687
http://www.debian.org/security/2008/dsa-1681
http://secunia.com/advisories/35390
http://secunia.com/advisories/33586
http://secunia.com/advisories/33182
http://secunia.com/advisories/33180
http://secunia.com/advisories/32998
http://secunia.com/advisories/32918
http://secunia.com/advisories/32386
http://lists.opensuse.org/opensuse-security-announce/2009-06/msg00000.html