Double free vulnerability in the init_ctx_reselect function in the SPNEGO initiator in lib/gssapi/spnego/spnego_mech.c in MIT Kerberos 5 (aka krb5) 1.10.x through 1.12.x before 1.12.2 allows remote attackers to cause a denial of service (memory corruption) or possibly execute arbitrary code via network traffic that appears to come from an intended acceptor, but specifies a security mechanism different from the one proposed by the initiator.
https://github.com/krb5/krb5/commit/f18ddf5d82de0ab7591a36e465bc24225776940f
https://exchange.xforce.ibmcloud.com/vulnerabilities/95211
https://bugzilla.redhat.com/show_bug.cgi?id=1121876
http://www.securitytracker.com/id/1030706
http://www.securityfocus.com/bid/69159
http://www.debian.org/security/2014/dsa-3000
http://support.f5.com/kb/en-us/solutions/public/15000/500/sol15553.html
http://security.gentoo.org/glsa/glsa-201412-53.xml
http://secunia.com/advisories/61052
http://secunia.com/advisories/60448
http://secunia.com/advisories/60082
http://secunia.com/advisories/59102
http://rhn.redhat.com/errata/RHSA-2015-0439.html
http://lists.fedoraproject.org/pipermail/package-announce/2014-August/136360.html
http://krbdev.mit.edu/rt/Ticket/Display.html?id=7969
http://aix.software.ibm.com/aix/efixes/security/nas_advisory1.asc