Several vulnerabilities have been found in the MIT reference implementation of Kerberos V5, a system for authenticating users and services on a network. The Common Vulnerabilities and Exposures project identified the following problems: The Apple Product Security team discovered that the SPNEGO GSS-API mechanism suffers of a missing bounds check when reading a network input buffer which results in an invalid read crashing the application or possibly leaking information . Under certain conditions the SPNEGO GSS-API mechanism references a null pointer which crashes the application using the library . An incorrect length check inside the ASN.1 decoder of the MIT krb5 implementation allows an unauthenticated remote attacker to crash of the kinit or KDC program . Under certain conditions the the ASN.1 decoder of the MIT krb5 implementation frees an uninitialized pointer which could lead to denial of service and possibly arbitrary code execution . For the oldstable distribution , this problem has been fixed in version 1.4.4-7etch7. For the stable distribution , this problem has been fixed in version 1.6.dfsg.4~beta1-5lenny1. For the testing distribution , this problem will be fixed soon. For the unstable distribution , this problem has been fixed in version 1.6.dfsg.4~beta1-13. We recommend that you upgrade your krb5 packages.