The (1) setfacl and (2) getfacl commands in XFS acl 2.2.47, when running in recursive (-R) mode, follow symbolic links even when the --physical (aka -P) or -L option is specified, which might allow local users to modify the ACL for arbitrary files or directories via a symlink attack.
http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=499076
http://git.savannah.gnu.org/cgit/acl.git/commit/?id=63451a0
http://lists.opensuse.org/opensuse-security-announce/2010-02/msg00000.html
http://oss.sgi.com/bugzilla/show_bug.cgi?id=790
http://secunia.com/advisories/37907
http://secunia.com/advisories/38420
http://www.mandriva.com/security/advisories?name=MDVSA-2009:345
http://www.openwall.com/lists/oss-security/2009/12/23/2